I've loathed every Mario spinoff game except the ones done by Camelot, since they seemed like the only ones that had some actual effort put into them.
Having said that, I'm hoping this game will be good. Sega's studios are pretty good if you don't count Sonic Team. So if they try and make this a good game, then everything's cool. If they're just gonna put another Mario Party level of development, but with just Sonic in it, then I hope it bombs.