I'm interested to hear what you find out about PDF's. I doubt I'd get the jetbook you got, but if they came out with an 8" or 10" reader, it might have a similar UI and internals, so it'd be good to hear how yours does.
I don't know what to say about the infamous e-ink page flip. Doesn't bother me at all. I've seen technology do far worse. I like how Jetbook's website says it will irritate your eyes. That made me chuckle a bit. I can see it irritating the mind, but not the eyes
Then again, maybe it's letting loose a snap of gamma radiation each time it does that! :-o