Overall, the Paperwhite 4 may be the best Kindle I have ever used, but not every change has been for the good, and in some ways, my earlier Kindles and the Kindle app are superior to the Paperwhite 4. My earlier Kindles are the Kindle DX Graphite and the Kindle Touch, and I use the app on the Boyue Likebook Mars, an Android ereader with an e-ink screen. I previously wrote a much longer review that was almost double the length limit. Then, I distilled the main points of comparison into some lists, which was much shorter but too bare bones. In this review, I will try to strike a balance by focusing on the differences between these devices that are most important to me. I hope this will help you make a more informed decision about whether to get the Paperwhite 4, stick with an earlier model, or get another device.ADVANTAGESOne of the best known differences between the Paperwhite and the Touch is that the Paperwhite has front lights. I was reluctant to get a Paperwhite in the past, because the lights could not be shut off. Thankfully, this has been fixed. I can now shut the lights completely off and use it as I would the Touch, or I can use front lights in low light conditions.One thing I really like about the Paperwhite 4 is the control is gives over fonts. I could install custom fonts on the Kindle Touch, but it didn't work as well as it now does on the Paperwhite 4. Before I could get fonts to be recognized on the Touch, I had to restart it or type ";fc-cache" into the search bar. With the Paperwhite 4, all I have to do is copy fonts to the /fonts/ directory on the device, and they are ready to use as soon as I open a book. On the Touch, I could not install more fonts than could be displayed on the screen at one time. To make matters worse, this space was shared with pre-installed fonts, and these included some foreign language fonts whose Latin characters looked the same. Thanks to displaying the custom fonts in a scrollable list, the Paperwhite 4 does not have this limitation on how many fonts I can install. With the Touch, it used fonts in the regular, italic, boldface, and bolditalic styles, but the Paperwhite 4 may use a font's full weight set.I expect this is because the Paperwhite 4 allows you to increase the font's weight by up to five increments. Including the normal weight, this provides six levels of boldness. This is nice, because making fonts bolder can make them larger and more legible without increasing the font size.I also like that the Paperwhite 4 has more gradations of font size than either the Kindle Touch or the Android Kindle app have. It has 14 font sizes, whereas the Touch and DX each have only 8, and the Android app has only 12. While I haven't had serious problems with the font sizes on the Touch, it has bothered me that the Kindle app makes a huge jump in font size between size 7 and size 8. The Paperwhite 4 does not have this problem. Making comparisons with the app on the Likebook Mars, which has the same PPI as the Paperwhite 4, the Paperwhite's size 5 is closest to the app's size 7, and the Paperwhite's size 10 is closest to the app's size 8. That means the Paperwhite 4 has four extra font sizes in the range where the app makes a huge leap in size. While I usually use the app with size 7, something slightly larger is more comfortable on the treadmill, because my eyes are further from the device. At sizes 6 and 7, the Paperwhite 4 still shows more text on the screen than the Kindle app does at size 8 on the larger Likebook Mars. But to get a larger size and a larger screen together, I end up using Moon+ Reader on the Likebook Mars. This app allows finetune setting of the font size by increments of one tenth of a point. I have been using it at a font size of 24 points, and in comparing this side-by-side with the Kindle Touch, this most approximates size 6 with a boldness level of 3. I have also used it at 28 points, which is somewhere between sizes 7 and 8 on the Paperwhite 4.One more thing that makes fonts look better on the Paperwhite 4 than on the Touch is that it has a 300 PPI display instead of a 167 PPI display. Comparing characters in the same font, they look smoother and more like printed text than fonts do on the Touch.Besides allowing custom fonts, the Paperwhite 4 comes with a larger selection of pre-installed fonts. In addition to Caecilia, Helvetica, and Futura, which I had on the Touch, it includes Baskerville, Bookerly, and Palatino. Of these, my favorite is Bookerly, a serif font Amazon had designed for reading books on e-ink displays. Even before getting the Paperwhite 4, I had installed it on my Kindle Touch and on my Kindle DX. The DX does not allow custom fonts, but a jailbroken one lets you change the default fonts. The Android app also comes with Bookerly, and since I cannot use it with custom fonts, I use it mainly with Bookerly.Another thing I like about the Paperwhite 4 is how quickly it handles page turning. Pages turn instanteneously without any noticeable transition effect or animation. On the Touch, there would be a transition effect as the contents of one page blurred into the next page. In the app, I can check or uncheck the option for a page turn animation, but when I do uncheck it, I get a shifting animation. In the regular display mode of the Likebook Mars, these can be visually jarring. This can be reduced by switching to A2 mode, which makes animations smoother by being more lax in what it updates on the screen. The main side effect of using A2 mode is ghosting, which means displaying after images of what was previously on the screen. This is not so bad that it impairs legibility, but it does make the screen look uglier. The Paperwhite 4 does not show any noticable ghosting. The main problem with the app seems to be that it was designed for LCD screens on phones and tablets, not for e-ink screens. On the Likebook Mars, Moon+ Reader, which has settings to accomodate e-ink screens, can do clean, instantaneous page turns in regular mode, and in A2 mode, its ghosting is less noticable. Unfortunately, it is no good for reading Kindle books.Something I like about both the Paperwhite 4 and the Kindle app is that they will let me mark books as read and then filter books by whether or not I have read them. When I just used a Kindle Touch, I kept track of what I hadn't finished reading yet by keeping it on the device while moving what I had read to the cloud. This did not work out as well with the Kindle app, because it would sometimes delete books on its own. Thankfully, it got the Read/Unread filters not long after I got my Likebook Mars. Now that I'm using multiple devices for reading Kindle books, having these filters makes it much easier to see only books I haven't finished reading yet in my library. Another helpful new filter is its Kindle Unlimited filter, which shows only what I have borrowed with Kindle Unlimited.One frustration I had with my Kindle Touch is that when I would search for a book title, it would search for the search term only in the text of books, not in titles. Instead of just showing me the book I wanted to find, it would give me a list of locations where that term appeared in the book. While this would also help me find the book, I could not effectively use it without losing my place in a book. So I'm happy that the Paperwhite 4 now does titles searches. Title search results appear underneath the search bar as I'm entering text. Since most of my searches have been for book titles rather than for book content, I'm glad that search now works like this.One new feature I noticed on the Paperwhite 4 is that it will let me change dictionaries on the fly. I also learned that the Kindle app has this same feature, though it implements it differently. The Touch does not have this feature. It lets you change the dictionary only by going to settings. The advantage of this feature is that it lets you easily use multiple dictionaries instead of with just one. I normally have The Collins English Dictionary on each of my Kindles, but now I can easily look up definitions in the Oxford Dictionary of English or the New Oxford American Dictionary. Even more significant than this, I realized that I could add translation dictionaries. With this in mind, I bought A Digital Latin Dictionary. With this, I could look up English definitions of Latin words. This is helpful, because when I have come across Latin words in the past, it was frustrating that the Kindle did not support translation from Latin.One of the defects in the Kindle Touch that prompted me to get a Likebook Mars is that its experimental browser does not always work well with HTTPS sites. After using Cloudflare to change my own websites to HTTPS, I could no longer load them in the experimental browser on the Touch. But the Paperwhite 4 does not have this problem. My own websites that no longer work on the Touch work with it, and I've come across other websites that work on the Paperwhite 4 but not on the Kindle Touch.This covers the main things I like about the Paperwhite 4 over the Kindle Touch and the Android app. The Paperwhite 4 and the Kindle app have many of the same features, because they both continue to get updates, but the Kindle Touch has a very different feature set, because it no longer gets updates. I have already mentioned the advantages of the Paperwhite 4 over the app. I'll briefly mention some more of its advantages over the Kindle Touch. It has twice as much storage space, its ability to display manga and comic books is less buggy, it has better support for magazines, it supports translation for more languages, it has Goodreads integration, it has Word Wise, and it has IPX8 waterproofing.DISADVANTAGES & SOME COMPENSATING FEATURESAlthough it has front lights, it has no warm front lights. Warm lighting has less blue light in it, which makes it more suitable for reading at night, as blue light can reset circadian rhythms and cause sleep loss. The one feature it has to make up for this is its inverted display mode, which shows white text on a black screen. This helps absorb more of the light from the front lights, and it makes nighttime reading more comfortable. In this mode, the lights cannot be shut completely off. But they will still go off if you put the device to sleep.One difference between the Kindle Touch and the Paperwhite 4 is in how they support audio. I prefer to have speakers and an audio port, which is what the Touch has, to having audio support only through Bluetooth. I already have earphones and speakers that I can plug into an audio port, but I have no Bluetooth audio equipment, nor do I have any interest in getting any. But this difference is not too important to me, because I have little interest in audio books, and the Kindle app supports audio books better. In the app, I can read along to a book while listening to it being read. As the text is read, it highlights the word being read, and when it gets to the end of a page, it automatically turns it. Used in combination with Word Wise, I can see definitions of unfamiliar words without needing to pause the audio to look them up. On both the Touch and the Paperwhite 4, there is no integration of written books with audio books. You can read the book or listen to the audio, but you cannot do both at the same time.In comparison to my dedicated Kindles, the Likebook Mars has much better support for audio. It has both an audio port and Bluetooth audio, though I use only the former. As an Android device, I can use it to stream music or play MP3s while I read. Unlike the Touch, which can also play MP3s, it can run apps that organize them and let me select specific albums to play. Also, the 128GB micro SDXC card I placed into it provides much more storage space for music.I prefer to read books without any auto-hyphenation of words that won't fit at the end of a line, which is how the Kindle Touch works. While auto-hyphenation does have the advantage of fitting more text on the screen, I prefer no hyphenation, because splitting a word between two lines sometimes makes it harder to quickly see what the word is, which slows down my reading. Unfortunately, the Paperwhite 4 and the Kindle app both auto-hyphenate words too long for the end of a line. It would be fine to include auto-hyphenation for those who want it as long as those who don't want it could turn it off, but there is no option for that. I see more hyphenation on the Paperwhite 4, probably because it has a smaller screen than the Likebook Mars.On the Paperwhite 4, footnote superscripts are smaller than they are on the Kindle Touch. This makes them smaller targets, which results in me missing them more frequently. When it shows the body of the footnote, it shows the first paragraph of the footnote in a special box that may appear along with the text, giving some context to the footnote, though usually this box is the same size as the screen even when what it displays could fit in a smaller box. In case of footnotes with multiple paragraphs, this box includes a link to the footnotes section, though it usually gives no indication as to whether there are more paragraphs. So, I usually go to the footnotes section anyway to see if there is more to the footnote. This is frustrating, because it adds an extra step to seeing a footnote. I prefer how the Kindle Touch handles footnotes, which is to go directly to the footnote section without requiring an extra step.The Kindle Touch let me run Active Content. These were like apps but designed specifically to run on Kindles. They include things like weather, a checklist, a note pad, a utility kit with a calendar, and some games. Thanks to now having my rooted Nook Simple Touch and my Likebook Mars, which are both e-ink devices I can run Android apps on, having active content is no longer as critical, though it is still nice to have. Unlike the Kindle Touch and some earlier Paperwhites, the Paperwhite 4 does not support Active Content.The experimental browser is not very good. It scores 0% on css3test.com and 152 out of 555 on html5test.com. It displays Wikipedia pages poorly even though Kindle books let you look up terms on Wikipedia. When a Wikipedia article has many references, it lists them in two columns, and this browser tries to fit the whole rest of the article into the first column. Its saving grace is Article Mode, which will let you view a Wikipedia article or any other article in a single column with a clear, legible serif font. But in general, it is not nearly as good as Chrome or Firefox on an Android device. The Likebook Mars has the advantage of being able to run these and other browsers.One frustration with both the Kindle Touch and the Paperwhite 4 is that the virtual keyboard has no cursor keys. This makes it hard to position the cursor when I want to edit text. With the Likebook Mars, I can get full cursor keys with Hacker's Keyboard.One thing I like about my Kindle DX is that it will auto-rotate the display to match how I'm holding it. Apparently, the Oasis 3 also has this feature. But the Kindle Touch, Paperwhite 4, and Likebook Mars all lack it. The two 6 inch Kindles let me manually select between portrait and landscape. An app I run on the Likebook Mars lets me choose from these and their reverse orientations. Reverse portrait lets me more easily hold the case with my left hand, and it would be nice to have the same option on the Paperwhite 4, since it fits in the case I got for it only one way.Another thing I like about my Kindle DX is how it tends to show large images, so that I rarely have to zoom anything. But on the Paperwhite 4, the Kindle Touch and the Kindle app, too many images appear smaller than they should and require zooming. This is not because the DX is larger. Even proportional to the screen, images on the Paperwhite 4 and the others appear smaller than they do on the DX. In some books, particularly the Graphic Guide Introducing series available on Prime Reading and Kindle Unlimited, many of the pictures show up very tiny and need to be zoomed. Worse than that, some images that appear very tiny cannot be zoomed, and those that can be zoomed sometimes have the x for exiting the zoomed image blocking part of the text in the image. I have read several books in this series using the Kindle DX, and images in these books always show up full size on the DX, so that there is no need to zoom them. If not for this issue, I expect these books could be read on the Paperwhite 4.Unlike the app, the Paperwhite 4 and Kindle Touch cannot display magazine pages as they would appear in the magazine. This is probably because it didn't make much sense to give this ability to a device that displays in black and white and is much smaller than the typical magazine page. In compensation, though, these devices provide better navigation of magazines, and they more easily spare you from seeing magazine ads. They let you read magazine articles in text mode, which does include images. The Paperwhite 4 does not let you use custom fonts when viewing magazine articles, though the Kindle Touch does.One last thing is that the Paperwhite 4 is not the ideal size for some types of content. Manga will look better on a device that is closer to the size of actual manga, such as the 7.8 inch Likebook Mars. PDFs, books with special formatting, such as the Dummies books, and books with wide tables will look better on a larger device, such as the 9.7 inch Kindle DX or a large Android ereader. Magazines and color comics may look better on an LCD tablet, since they use color and are normally larger than the 6 inch screen of the Paperwhite 4.PAPERWHITE 4 VS THE BASIC KINDLE AND THE OASIS 3I do not have either of these devices, but their firmware is very similar, and they mainly have a few hardware differences. The main advantage of the Paperwhite 4 over the Basic Kindle is that it has a higher PPI. Seeing how much smoother and cleaner text looks on the Paperwhite 4 than on the Kindle Touch, which has a lower PPI, I consider this a good reason for preferring the Paperwhite 4 to the Basic Kindle. The Oasis 3 has multiple advantages over the Paperwhite 4. It is larger, has auto-rotate, and provides warm lighting. The main advantage of the Paperwhite 4 over the Oasis 3 is that its flat design is better suited for laying flat on a surface, and this comes in handy when I want to read on the treadmill or exercise bike or use a tablet pillow in bed. It also makes it easier to use it with a case. I bought a third-party case for my Paperwhite 4 with a vertical strap on the inside front cover. This makes it easier to hold onto. To hold it more comfortably, I sometimes slip underneath its vertical strap a looped strap for anchoring resistance bands to a closed door, then slip one hand through its loop.CONCLUSIONIn conclusion, the Paperwhite 4 is a great ereader, though it is not as good as an ereader could get, and it is not ideal for every use. I do not recommend it for audio books, manga, comic books, books with many footnotes, books with many illustrations, books with special formatting, or books with wide tables. But for books that are mainly free-flowing text, it's a great choice. It would make a good first ereader, and even if you get another ereader for content it doesn't handle so well, it's a good one to have around for regular books. The 6 inch size is comfortable for reading, and it makes it more portable than larger ereaders.