I'll definitely throw my hat in with the SNES version. The Genesis version had an art style that was closer to the movie's animation, but wasn't nearly as colorful as the SNES version.
Virgin Interactive was known for producing a lot of the Disney-liscenced games, and they were known for making some really good sprite animation. So it doesn't surprise me that a lot of people remember the Genesis version fondly for its impressive animations.
In the end though, I still prefer the SNES version, largely for its gameplay, and surprisingly tight controls. I'll echo the claims of solid platforming. They designed the levels well to reward players who had learned to use the controls effectively.