I Zbattle quite a bit and I'm using a stock PSX controller (not the chunky dual shock) and personally I think it suites the SNES perfectly. ABXY map perfectly, nice sturdy D-pad and LR is great too. Why not a genuine SNES controller though you're probably asking? Well, considering SNES's age the controllers in existence are probably worn severly, like mine here

My next reason is that in my personal opinion, the PSX controller is superior to the SNES controller for SNES play. Its just that, when I imagine a SNES controller new, with nice responsive controls I can't imagine that I would choose that over the PSX controller. It just feels so much more comfortable to handle and play with than the SNES controller. I know theres probably not that many people who would agree (what with the 'its not the same without the original' argument) so just remember is MY personal opinion

Just a quick rundown for what I find useful in Zbattle:
SUPER MARIO KART
My most played game on zbattle

CONTRA 3
Very useful setup with PSX controller. I map X button to R2 for very easy switching of weapons rapidly for the ultimate in firepower. Superb control in this game.
TETRIS ATTACK
Hmmm, I'm a bit slow on the cursor but I can still pull the odd 13X chain should the oppurtunity arise. D-Pads very nice here and I'm precise with the movements here.
Well, theres my most played games on zbattle. So what gamepad to you use for your competitive (or offline) play?
Oh and I'm not sure if this should go in zsnes talk or controller help...Its controller related but I'm not asking for help
