It just depends on what genre and what you're looking for imho
The Genesis had a bigger resolution which is really important for some games, the one that comes to mind for me is zombies ate my neighbors. It's really hard if you can't see more of the screen. Earthworm jim is another I believe, especially certain levels in the second (iirc)
The Genesis was also generally better if you needed speed, like in shmups
But the snes had a lot more colors and bigger pixels and the sprite rotation stuff which made some games better looking on it
Why did the Genesis have higher resolution when it's over 2 years older?