I'm gonna say Mario because they were always able to upgrade him and make better and better video games. From back in the NES days to SNES to 64 to Gamecube to Wii. Not to mention, back in the day, Mario 1, 2, and 3 were all completey different video games. Unlike Sonic where they were all the same and eventually got boring.
Mario's spin offs are a lot more fun too. Especially Mario Kart.
Mario he's had more of an impact on the genre. Are we forgetting that Super Mario 64 was the first 3D game EVER?
Agreed. Mario is practically the icon of the Video Game buisiness. There isn't a person in the world that wouldn't recognize him after seeing him. And isn't Super Mario Galaxy the first kind of planety-a-lot-of-gravity-switching-game ever too?