pocketsnes is allright for me although some games have been to slow to even play, but some have ran ok like Zelda 3, as for sound I haven't even played with it on yet cause it slows it down. Configuring buttons is also an issue if you do use it I recomend dowloading the program on this site to make the navagation button another control option when pushed in. Anywsy give it a try and see what games work.
by the way i only have an x5 basuc so this may have something to do with the spped of games as well.
I have an x3i and run pocketsnes bleeding edge, which works great. I run sound most of the time which doesn't seem to slow down the game play much at all but the sound doesn't sound to great but it's good enough for me.