When I was writing my “first day review” about Kindle 3, I promised to get back with some experience after more days of using. Well, here it is. Two weeks of usage.
My initial worries about space where to place thumbs was false, kind of. I developed new way to grab Kindle, because it’s smaller and lighter and because the place together with buttons isn’t large. Not an issue anymore.
Mentioning the buttons, previous and next page buttons to be precise. As I wrote, the buttons are around the edge of device, so when you press one, it goes little bit of the device on the bottom. And you can also press it by grabbing Kindle on both edges. But I simple untaught myself grabbing it that way 
, not a big deal. And feeling the button from the bottom? No problem, I got used to it. The buttons are smaller, so now I’m pressing these by tip of my finger, not whole finger as I was. I think it’s just a different way for different model. Both moves are equal for me.
After two weeks of usage I don’t have enough samples to judge the battery life. But from the way the battery icon looses it’s fill I’m sure it’s not worse than the previous one. My guess is, with 3G and/or WiFi turned on and occasionally using these plus heavily using the device for reading, it would take roughly two weeks to get fully out of juice. With all networks turned off (and using it of course ), probably about a month, similarly to previous model (which I can confirm). From my experience with previous model these numbers are more than good to forgot to charge it before you leave for business trip (and of course forgetting cable). 
Good enough for me.
The new Kindle still outruns the old one very. So far I didn’t find any problem that would make me regretting the buy. I would still recommend it to anyone who loves to read. And a recently discovered way to get documents into it for free without having to plug it in using cable, it’s my primary device for all content I read that takes more than minute or two to read.