Snes9xGP 0.72a: Decent speed on a limited number of games without sound, even more limited with, but sometimes playable - just test a few games.
SnesGP: Good speed, but no L/R keys... its got a file selector, but no sound or save - both of which I hope desperately to see in a future release.
InfoNES: Slowly becoming more and more playable with both sound and save - no need for screen stretching - 0.2 was good for many many games, and I'm assuming 0.3 beats it further.
Wonderswan: Funs FF1 & 2 at full speed (or seems so) - needs FS 3 though, but certainly playable. Savestates mean you can save, and although there's no sound yet, the thing is perfectly playabe. I wish it had screen stretching though. The author HASN'T given up completely, just put it on hold, so it might see further development.
TG-16 I can't really talk about - many of the games I tried on it don't work properly.
Oh, and Plus/4 emu by CHN runs many games at at the least, playable speed (seems full speed, but someone mentioned the next ver would be 10%, so perhaps a tad slow atm...?)
fMSX: Is still being worked on, and from what I hear, coming along **very** well...