I don't know if the analogy is perfect, but I think of Amazon's new Kindle Paperwhite as the iPhone 5S of e-readers -- it looks nearly identical to the original Paperwhite, but it's zippier and better.
For starters, the new Paperwhite is the first shipping product to feature E Ink's Pearl 2 display, which offers better contrast, along with 1GHz processor (25 percent faster than the 800MHz found in the original Paperwhite), a next-generation built-in light, and a more responsive touch-screen display (1,024x768-pixel resolution with 212 pixels per inch) that has a 19 percent tighter touch grid. It's also a hair lighter, weighing 7.3 ounces instead of 7.5 ounces.
While the two models look the same (there's an Amazon logo on the back instead of a Kindle logo), the most immediate difference you notice is that the display looks whiter -- as opposed to having a little bit of blue twinge -- and the lighting is more uniform (the light is also brighter at its highest setting).
On the original Paperwhite, there was a bit of murkiness (sort of a clouding effect) at the bottom of the display when using the light, particularly at night. The light now displays noticeably more evenly across the bottom and the rest of the screen.
Compared side by side with the original, the old Paperwhite's display does look a little dull and gray (with that blue twinge). The official company line is that the "whites are whiter and the blacks are blacker, so pages are virtually indistinguishable from a physical book." I wouldn't quite go that far, but the display -- and reading experience -- continues to improve and looks more like a printed book.
Amazon encourages you to read with the light on, though not necessarily at full brightness. It's nice that you can easily adjust that brightness, but it's worth mentioning that there's no dedicated physical button for turning the light on and off like there is on the Kobo Aura. You simply use the onscreen slider control to adjust brightness or turn the light off altogether.
Of course, some people don't like to read with the light on when they have ample natural light (or are in direct sunlight). With the light off, it becomes much harder to tell the difference between the the original Paperwhite and the new model. Both editor David Katzmaier and I also thought that text looked slightly sharper with the light off. Katzmaier, CNET's home video guru, uses the now-discontinued 2011 Kindle Touch regularly and wasn't a fan of the slightly flawed lighting scheme on the original 2012 Paperwhite. However, he says that given the choice today, he'd opt for the new Paperwhite over the Kindle he uses now, as well as the $69 entry-level Kindle (which lacks both a touch-screen and self-illuminated screen).
Amazon says the contrast has been increased, but it's hard to tell that the blacks are that much blacker, even if they are. (Peter Larsen, VP of Kindle product management, told me the percentage increase is "double digits," though it varies slightly with each batch of e-ink so it's hard to put an exact number on it.)
The new display requires less refreshing, which is sometimes referred to as flashing (e-ink screens need to be refreshed every so often to eliminate artifacts or "ghosting"). The previous model refreshed every six page turns and in my tests with the new model it refreshed every 13 to 14 pages.
As for battery life, it remains the same at up to 2 months with Wi-Fi off despite the bump in processor speed. To conserve battery life, it's crucial to keep Wi-Fi off. While the "experimental" Web browser remains on board, you really only need to turn Wi-Fi on to buy books (or load ones you have stored in the cloud) or download newspapers and magazines (subscription required). You can also email documents and Web articles to your device, though the Paperwhite isn't packed with storage; it comes with the same 2GB of integrated storage (1.25GB available for user content), which Amazon says allows you to store up to 1,100 e-books. A Japanese version will include 4GB of storage.
Along with the original Paperwhite, I compared this model to Kobo's Aura, which is a nicely designed e-reader that's smaller than the Paperwhite, despite including an identically sized screen. I like the Aura, but the screen and lighting are better on the Kindle. It's not a huge difference, but it's definitely noticeable, and the Paperwhite costs less, starting at $119 for the Wi-Fi-only model that serves up ads -- Amazon calls them "special offers" -- on your home screen. You can opt out of the ads for $20 extra, either at checkout or at any time after you buy the device, so it's worth going with the cheaper model first. A 3G-enabled model -- which lets you access Amazon's store over a cellular network at no extra charge -- will ship on November 5 for $189 (or, again, $20 extra to avoid the ads).
Software changes and upgrades
The rest of the changes involve feature upgrades that Amazon has -- or will -- add through software updates.