Hey guys, I just happened upon this thread in a Google search. I've been a GP2X user for 2 years now and I think it's great. For more info on the GP2X (and the crazy-powerful GP2X successor, Pandora), head to the main community sight at
www.gp32x.com
One of the main problems with the GP2X has always been it's battery life. For most users, they last between 3-5 hours, depending on the quality of your rechargable bateries and battery charger. The positive aspect of this is that you can replace the dead batteries with fresh ones at anytime, unlike a built in battery solution.
I honestly think GP2X is the best emulation handheld at the moment. Most of the great PSP emulators right now are ports from the GP2X. Picrodrive for example, started much of its life on the GP2X and its version still remains faster and more optimized. PSP does have great PS1 emulation though, which currently runs slow on the GP2X.
Anyway, I could go on and on about this topic, but I won't
If you have any questions, I might check back once every few days to answer them.