New Kindle Fires
The two highest end Kindles have an 8.9" screen, and are priced to compete with tablets like the iPad. They're cheaper, but have a smaller screen and a dual-core, rather than quad-core, processor. Amazon must be betting that the budget conscious will compare the two options and decide that the Fire better fits their needs. I suspect folks are more likely to pick an older iPad, but we'll see.
The new Fire at the low end, the Kindle Fire HD, is a less ambitious follow-on to the original Kindle Fire, having approximately the same size and price as the original. But it still fulfills my wishlist of improvements. Aside from the standard next generation upgrades, such as improved processor (marginal upgrade from OMAP 4430 to OMAP 4460, both dual-core), memory (doubled to quadrupled), and screen resolution (upgraded from 1024x600 to 1280x800, enough to support 720 HD), it also has almost all the things I've been missing in the original Kindle Fire.
First and foremost, they've fixed the sound. This was a significant issue in the first Kindle Fire, which only had two tinny speakers located at the top of the tablet. Which really made no sense, since when you're watching video (which is the only time when I really need the sound), you hold the Kindle sideways. So the stereo speakers Amazon advertises are both on the left side of the Kindle while watching a movie. Not to mention that even at full volume, I couldn't hear them over the air conditioning in the bedroom. I usually just wore headphones when watching video, but it'd have been nice to have the option of using the speakers. This time, Amazon went out of the way to fix the sound, so the new Kindle Fire has dual-driver stereo speakers on both sides of the Fire when you're holding it sideways to watch a movie, and they make a big deal about how loud and clear it is. If it's as good as advertised, that fixes a major problem of the original Fire.
Second, they've added a micro-HDMI port. This was one of my gripes about the Fire, as I'd like to display its content on my television but I was unable to. I'm glad that they've fixed this.
Third, they've improved battery life, now claiming 11 hours of continuous use, as opposed to 8.5 hours. This is significantly closer to my assertion that the Fire needs a full day of use in order to fit in with Amazon's other e-readers, which is closer to where the Fire's positioned than the tablet market. I'd never really had a problem with battery life, but that's mainly because I've never spent a whole day reading from my Kindle.
Finally, they've added an inward-facing camera. They advertise that this is for use with Skype, but it should be usable for other situations where you need to take a picture of yourself. The iPad also has an outward facing camera, but for the most part, you aren't going to be using the camera on a tablet to take pictures or video, so it's not really a necessity. It is nice when you want to show the other person in a video chat something, but I've discovered that most people don't really know how to use that feature.
Unfortunately, they haven't added a microSD card slot, which would have allowed the user to expand the memory. I would have liked that option. I'd also have liked seeing an AMOLED screen, as opposed to an LCD, but that's still a new, high-end technology, and Fire's definitely positioned at the budget end.
Anyway, the new Fire HD has enough improvements that I'd seriously consider getting it if my wife would let me. But she points out that she got me the Kindle Fire for Christmas last year, and she'd be a little insulted if I replaced it after less than a year. So I'll at least have to wait until January.
New Kindle e-inks
The new kindle e-inks are very different creatures from the Kindle Fire. They clearly are not tablets, and are not designed to be. They're e-readers, with e-ink displays that are low energy (giving battery life in the weeks range), easier to read in sunlight, and slow. Going to the next page on an e-ink display can be slower than turning a page in a book, and they often invert when doing so in order to refresh the electronic ink, which I find annoying. Newer Kindles allow you to turn the refresh off, so the page only refreshes every six turns or so, which is good.
The new Kindle Paperwhite e-readers offer some significant improvements over the old Kindle e-readers. First, they're touch screens, which is something Amazon introduced in the last generation, but is now making standard. Second, the contrast is much greater. Earlier Kindles had a gray background, with black ink, but the Paperwhites have a white background, which make them more attractive and easier to read. Additionally, they're lit. I've seen people call them backlit, but that's not really the case. They use a waveguide over the screen to direct light down to the screen, where it will reflect back up. This should cause less eye-strain than backlit screen, while providing nice, even lighting over the whole page. One of my main reasons for getting a Kindle Fire rather than a regular Kindle was so I could read in the dark, so this is a great feature.
So what is it still missing? Well, I didn't see any indication that the page refresh has been improved, so it doesn't need to invert as often and leaves fewer artifacts, but such a marginal improvement might not be important enough to be advertised. I'm also still waiting for someone to come out with a color e-ink reader. It can be done, but I don't think the technology's ready for a commercial device yet.
ComparisonThe difference between the e-ink Kindle and the Kindle Fire is not the price, since they're pretty close on the low end. They're very different systems. The Kindle Fire is not just a reader, but a full media player and a capable, if low end, tablet, with a large number of Android apps available. The e-ink Kindle is an e-reader, and is probably a more comfortable platform for reading--even in the dark, now that it's lit. You get longer battery life, and free 3G data on the high end models (4G is only available on the most expensive Kindle Fire, and while cheap, is not free). The e-ink Kindle is just pretty limited on what you can use that 3G for, as it's too slow for much web browsing, and incapable of doing video at all. But you can download Kindle books to your heart's content.
Overall, though, I think I'd prefer the Kindle Fire HD.
Update (9/9/2012): Here's a hands-on look at the new Kindle Fire HD. (hat tip Instapundit)