I agree with Doom for once! But I don't take those areas as equal, I put them in this order:
1. Video (of course)
2. Sound (almost as important)
3. Netplay (a great feature but not essential)
4. GUI (got to be simple like Snes9x, but got to be nice looking like ZSnes)
5. Speed (my comp can handle both easily, so less important for me)
6. Portability (got to feel for non-windows users! Doesn't apply to me)
7. Save states (rarely if ever use them, they ruin most games if overused)
...and ZSnes won two out of the top three aspects according to Doom, explaining my ZSNES choice.
Anyone who doesn't understand ZSnes Netplay obviously hasn't got zBattle.net, from
www.zBattle.net makes it so so easy, no IP addresses or nothing, just join a game similar to online PC gaming. You cannot do this with Snes9x!
If you know anything about me, you know that I like to test to the absolute death, and I have the very latest of both emulators, and I must admit that Snes9x is approaching ZSnes fast, with the sound being finally at the right pitch.
This is a difficult issue! Just go with any. I made my choice, I started with Snes9x (when I first started emulation!) and moved on to ZSnes when I started to 'know things'
Oh, ZSNES WIP April 14 has been released.
You know the drill:
http://ipher.znes.net/