I have the first version and I love it. It's easy to read, lightweight, and they make it super convenient to order books via wireless delivery. I got it last year when I was doing a lot of travel and it allowed me to carry only one small thing but have literally dozens of books.
I don't plan on upgrading to this version, but as soon as they come up with one that can handle color graphics (versions 1 and 2 are black-and-white only), I'm getting it!