After lots of trial and experimentation with multiple titles and about four different SNES emulators, I'm generally finding SNES emulation to be OK but definitely some titles that are basically unplayable no matter what the emulator or setting. SMW 2, for example, and Star Fox are some of those that may work if you can tolerate a frame skip of like 4, but you either have to tolerate that or unbearably slow speeds. Even something like Megaman X2 where at the boss of the intro stage experiences significant delay because of all the on-screen elements requires a frame skip no matter what the emulator. So the answer I've found for my question as to the present state of SNES emulation on the PSP is best summed up as "ehh, may work, but leaves a lot to be desired."