I tend to switch between MorphGear's NES/SNES emulators and PocketNester/PocketSNES-GL. It's a pity Morphgear has be hacked up before it works with GAPI reasonably, and even then it's a bit buggy because you get toolbars disappearing and all sorts of other annoyances.
They need to get their butts into "gear" and patch us up a nice VGA compatible version! :)
Still, it's a very good emulator. I hope they manage to keep development going and get some better Genesis and GBA cores working.