As far as the games go, Mario wins it. As far as the individual characters are concerned, Sonic is cooler. Fast is fun what can I say.

And for the record, Sunshine was fun, but it wasn't as good as Mario 64. I mean, heck, Mario 64 had more levels and more variety than Sunshine, and I didn't like losing the long jump for that slow and rather boring hover feature. Sunshine was also a little too linear if you ask me. Fun none the less, but a definite step back for the series.