Well... code checking in GeePee32 is doable (kinda), but its not fast by any means... **never** use it as a method of judgment on how good a GP32 is, regardless of the fact that its emulating a 133MHz machine on one with a few GHz - its still slow for all but games made specifically for GP32; it ain't good with emu. At all.
It's good, I imagine, for testing if code works, though. It just isn't fast.