Mario because I like both the old games and the new ones. Sonic is good, but I only play the old games. I like almost all the Mario characters, but Sonic..eh..too much unneeded characters. Mario helped the platform, sidescrolling games and stuff like that, Sonic helped break a new style of platforming yet still offers adventuring and stuff like that. Mario is basically a warm strong man, Sonic is a cool hip hedgehog. Though, overall, Mario is the best because of the flexibility of his games and better adaptability to the 3D era.