I like what he's done so far. I'm going with above average though, since he hasn't had a real 'moment' in my eyes. And some of the throws like the Int into double coverage at Tennessee, or the Driver TD in double coverage. It's great when it works, but it holds alot of risks.
Matt Cassell is 5-3 now and Byron Leftwich has a 117.4 rating. Both of them aren't great. I think you have to look at everything in perspective; team, ofcourse the QB himself an what not. For example a player that has played for the league for a long time. his rating shows you how good he has been, playing for nearly 20 years. But he's been a 95.8, supberbowl winning QB, but also a 70.9, 4-12 QB, mostly depending on the rest of his team. So I don't hold on to either stat on the short term.