Not got off to a good start there fella's lol (I hope thats not really your DS Horace!)
Pspuae 0.72 offers certain games good speed and certainly good playability, the problems are when you pick a certain game that runs badly on the emu, and it's config is setup badly to, Then things can look pretty ugly.
My advise is to pick a game that runs well (hopefully it's one of your favorites) then set the frameskip between 30-39 rather than auto.
set the turbo to on, change the cpu to chipset ratio to 30-65%. I find these three things are the most important with lots of games.
It's a matter of setting each game up manually to achieve the best speeds/smoothness and playability.
It can take some time to experiment with what works best for each game, but it can lead to pleasing results if your willing to put te effort in for your favorite games
I also recommend you search the
http://www.youtube.com/pspuae for the game your looking for (hopefully its available to view)
You can then see how it should run on pspuae and decide if it's worth trying out.
I've never seen the GP2x running Amiga games first hand, so it's hard to compare to pspuae.
What I do know is, FOL and Horace have spent lots of their time trying to get things running fairly well. Its come a long way from it's early days.
Amiga emulation on a psp is very difficult to achieve, especially compaired to SNES, NES systems ect.
Hope this seems to help, please try a few more games and experiment with the settings, I'm sure you will be able to find something your happy to play. I have found many games that are very playable and give hours of fun.