Sega spawned Sonic which spawned the Sonic the Hedgehog cartoon.

Nintendo spawned Mario which spawned the Super Mario Bros Super Show.

The Sonic cartoon was clearly better. Sega does what Nintendon't.

Seriously though, I think I do like Sonic over Mario when it comes to the SNES/Genesis days. But when it comes to other games outside of our two mascots, I still say Nintendo has the edge for me personally. This is simply due to nostalgia factor, I'm sure. I played more NES/SNES/GB games as a kid than I played Genesis/Game Gear games. My family simply owned more games for the Nintendo systems. I think all I really had going for me for the Genesis was the 3 Sonic games and Quackshot Starring Donald Duck. I may have even had more Turbografx games than Genesis games.