What is the best fighting game on SNES in your opinion?

For me it's Super Street Fighter II - The New Challengers.

Imo? SF2 Turbo, hands down, easily.

Street Fighter Alpha 2

Street Fighter 2 Turbo.

The list of good fighting games on SNES is pretty short. The only real contenders, IMO are MKII, UMK3, Killer Instinct, and various versions of Street Fighter 2. Alpha 2 is cool but I think it had framerate issues. I'll choose MK2 because I'm not a fan of Dail-A-Combo and there's much better versions of Street Fighter 2 on other consoles. 

I enjoy Killer Instinct and SF2 but MK2 and MK3 were my jam

Lowkey Clayfighter 2 as well. That game was loads of fun.

I'd give Super Street Fighter II the slight edge over Turbo.

Turtles Tournament Fighters is fun too but nowhere near as good as SF II.

I forgot that existed despite owning it. Definitely a solid fighting game. Especially the SNES version. 

Alpha 2 is technically impressive on SNES.

Although, I heard the PS1 version runs much better.

Saturn version runs best of all. Saturn was just better at handling 2D games than PS1 due largely to the ram carts but also due to being built for high end 2D games. Sega didn't think 3D was that important at first and initially designed the Saturn as a 2D powerhouse. Extra hardware was added to the Saturn late in design to make it more 3D capable. Saturn and PS3 are both technically more powerful than their competitors but hard to code for.