In my haste.. I accidently selected GBA.
Trust me - GP32 rocks. Better than GBA in so many ways. The community is fantastic - like the Amiga community used to be. Dev is too a penny.
The machine may be limited by 8mb on board which prevents some emulators from working at their best - eg 8mb prevents roms from being fully loaded in - but you can solve this with the 32mb hack.
Plus there is ample home brew dev - and native software. Origional titles which are great such as tomak saves the earth again.
Emulation is its biggest draw. Thankfully the GP32 has a flashible ROM - which has space for lots of different firmwears. A GBA emulator was thought impossible at full speed due to the GP32's own overheads. But one clever chap is in the process of writing a firmwear that enables you (much like the amigas early start up control) to reboot your GP32 into a GBA mode - thus freeing overheads and opening the GP32 upto GBA :-)
If you are going to buy one - go for a FLU unit, so you can play at night. GP32 standard unlit is more visible than GBA origional unlit anyway.