I use Snes9x for emulation. Although they are both really good emulators.
Snes 9x:
the sound is not choppy for me(except Clay Fighter)
Compatible with every game I have played (except Star Ocean)
Able to play games when they are compressed into .zip format
ZSNES: what is better than Snes9x
Windows version does not work for me, but DOS does
Graphics are sharper
Use of the Lethal Enforcers Gun
(with windows) Zbattle.net, a toll that I think is very important to any emulator, to have an online gaming server for the emulator because Kalliera sucks, and I can play people other than my friends that use emulation devices.
Both of them are fast, both of them are great, Both of them are better than the rest.