I don't mind the cramped keyboard, as long as it's QWERTY. I'm using a 8700g now, and this would be a bit more cramped. But I've used a Treo 650 (before I switched over to BB), and typing on that was ok.

But I sampled an 8100 at a T-Mo store, and I have to say: I HATE that little trackball! A trackball is good for playing "Missile Command", but not much else.
I'm gonna stick with the side scroll wheel.