The problem is that Sonic can't store his rings and the battlefield i presume happens in a dimesnion that isn't Sonic's or Mario's. So after the chaos energy (The Free 50 rings) runs out Mario can toast him.
And i am not really biased to Mario as you know it's just how i think things will turn out.
Also don't forget the stop watch : thats an instant game ender for sonic.
Luckily for Mario Sonic can't outspeed time unless it's the comic series Sonic but i asume we are talking about the one in the games.
Jesus Stop watch can be troublesome even for Shadow because manipulating time is hella lot harder then space.
Now if it was Luigi VS Sonic i would be super biased and would grab for every little thing like people on brawl boards do when doing the canon battles.
