I liked him at UNC, and last season, he seemed to be an absolute Knick killer (do you guys not remember all our close games with Charlotte last season? It was Felton who constantly hit a dagger three or laid the ball in during the final two minutes) But considering we had Duhon guarding PG's, and David Lee protecting the paint, pretty much every PG scorched us.
One thing though is that at UNC, he excelled in an uptempo offense, but then struggled in the NBA playing slower half-court sets. Moreover, Charlotte had some really awful offensive teams during Felton's first three years. Don't forget they were an expansion team whose best player was Okafor. His last season may have been a fluke or it could've been a product of playing on a decent team for once. I mean when you look at his teams, Felton never even got to play with a big man as skilled as Amare, so we'll get to see how good he really is at the PnR.
Personally, I think it's a solid signing, doesn't hurt our ability to sign a max in 2011, and if it's only 3 yrs as reported, he's still tradable if we want to upgrade to Tony Parker or Chris Paul. But we couldn't sit tight with NO point guards on our roster, hoping that we could trade for Parker or Paul. We needed a floor general now, and Felton can definitely fill that role for a couple seasons. And who knows, playing under D'Antoni and in an uptempo system may bring out the best in his game.
edit - I should also add, this guy is definitely a good defender too. He does a good job pressuring ballhandlers with good lateral quickness. And he has some good strength so doesn't get backed down easily. I believe he also guarded 2's when he played with Augustin in the backcourt. He did get burned by Nelson in the playoffs, but that usually isn't the norm.