I've had my Kindle Paperwhite for a couple of weeks now. It's the Wi-Fi model, because I don't think I'll ever be on the move so much that I'll require 3G. If I'm going anywhere, I'll just download a bunch of books on the Kindle so it will be good to go. The Kindle I had before was the basic one, which doesn't really explain it well because there have been a lot of basic ones out since the Kindle's initial launch. But the thing I liked about that one is there were buttons on either side to click to the next page. There aren't any buttons like that on the Paperwhite. In fact, the only button it has is the power button on the bottom.
I got the actual Kindle case with the Paperwhite, opting to spend a few more dollars instead of going with an eventual knockoff. I'm sure the knockoff works just as well, but I'm very happy with the case. The Paperwhite fits snugly into it, and when you open the front (assuming the Kindle isn't powered off), the screen will wake up and prompt you to swipe the bottom of the screen to unlock the Kindle. Then, once you're in, it takes you either to the page you stopped reading on, or to the home page.
I have the ad supported Kindle, because the ads don't bother me -- either a small ad at the bottom of the home screen, or on the entire screen when you wake it from sleep, and that's it. Not once is my reading experience ever hampered. In fact, sometimes the ads include special sales on ebooks and mp3s, which is a plus.
The touchscreen is extremely well responsive. I don't remember ever having any issues.
What strikes me the most is the pixelation of fonts -- there isn't much of any. It's quite sharp, especially when compared to the previous generation. You also have the option of changing the font itself, though some publishers restrict this option for some reason (Telegraph Avenue by Michael Chabon, published by HarperCollins, for instance).
The Kindle's name Paperwhite comes from one of the biggest features: "Patented built-in light evenly illuminates the screen to provide the perfect reading experience in all lighting conditions." For starters, the light isn't nearly as bright and white as the pictures on the product page make it out to be. I generally keep the light on high while indoors, though outdoors, in the sun, you don't need it at all. I will point out there is a slight shadowing on the very bottom of the screen, as seen here (and in the previous two pictures, if you hadn't noticed):
Again, it's slight, and I'm not even sure if it comes up as well here, but at first I thought the Kindle was broken. But then, after doing a few quick Google searches, I found others had this same problem, and that it is, in fact, a standard problem, but one that Amazon doesn't readily announce. Still, once you get used to it, it's no big deal.
In terms of battery life, Amazon claims "8-week battery life, even with the light on." That, I think, is a stretch. Like I said, I keep the light on most of the time, and I might get through a week before having to recharge it. Which really isn't that bad, if you think about it. Plus, most of that time I have the Wi-Fi on, so there's that.
Anyway, am I happy with the Kindle Paperwhite? Yes, very much so. I'd give it 4.5 stars out of 5 because of the shadowing issue, which I'm sure they'll perfect next year for the next generation.
What did I end up doing with my old Kindle? I donated it to E-books for Troops, a great non-profit that provides ebooks to military personnel deployed overseas. If you have an old Kindle sitting around collecting dust, I encourage you to donate yours. It's the least you can do.