Who do you think? I personally think Mario because all Sonic over there, can do is run and jump. Mario can run, jump, shoot fire from his hands (I mean the Koopas are just crying "Pwn me Mario" with that awesome power!) So yeah I pick Mario. F.A.B
Well, if you were trying to make an accurate comparison, Sonic can run *much* faster then mario, roll into a ball & use his spines to attack his enemies, use the power of chaos emeralds to turn into another form that's even faster (to the point where he's practically flying) and use magical rings that make him impervious to harm while he's holding onto them.
And don't forget all of the other things mario can use in SMB3, like the leaf, tanooki suit, frog suit, hammer suit, etc.
For important reasons I change my original choice from Sonic to Mario. Though Mario may look awkward compared to Sonic and "less cool", he's awesome!
Sega was just looking for something that might make them cool.
Yes, that's right. They tried to make themselves look "cooler" by creating and advertising Sonic. They claimed he was much cooler then Mario. However, right now Sega is a failure. The Dreamcast forced them to quit the video game business.