While Sonic Colors seems to be the first decent Sonic in a while... I'd definitely make sure Sega isn't pulling your leg before jumping into the buying process.
Take the money nas, it might be the only money you come across in a while, and there are plenty of games coming out that look like safer and more high quality guaranteed than sonic colours. For example, skyward sword, DKC returns, or you could save up another 150-200$ to buy a 3DS