Not too many lefties in the league who can pump 95+ with a great curve and change. The biggest difference I've seen in him since the turnaround in 05 is that he is more of a pitcher now. He is not always trying to overpower with his FB but taking some speed off in favor of command and utilizing a lot of his other pitches to set up.
His peripherals look like a near-elite pitcher's and if he continues to improve, he will be up there as soon as 07. He does need to lay off the donuts in the off-season though.