i have a cybook gen 3, and like it so much that i am getting one for my husband.
likes:
it's very light
it's got great mobipocket support
in the cover, you can hold it just like a paperback
it's easy to use
you can just read and read and read on it
cons:
worry about the screen, but i'd feel that way about any eink reader
i like mobipocket as an ebook format because unlike some other formats, i can read the ebooks i download on my computer, my netbook or my pda. in fact, mobireader is even cooler on my computer than on my cybook
btw, it's a rare person who could enjoy reading for hours on an iphone screen. yes, there are a few folks, but for most of the people i know, it's just too cramped. do you know what the battery life is like when using it to read?