I personally feel people have overreacted about the recent games. I mean, only three games in the last four years people saw a problem with, and that outweighs everything else done in that time? Something's wrong here...
I really liked Sonic Heroes because of it's simplistic style. It was made to reflect the 2D games, after all.
Shadow the Hedgehog was good. It had great replay value with it's many different endings.
Sonic NextGen may of had it's problems, but I had the most fun playing it.