He's not the athletic freak Marion is. He doesn't get off the ground like that. He's also not the defensive rebounder that Marion is.
Right now he's got two problems:
1) His handles. Last year they were downright terrible. They're now good enough that if he's in the open court and he keeps it simple, he won't turn the ball over. But he's got a whole lot of work to go if he wants to be able to create his own shot regularly without turning the ball over.
2) Outside shot. Wildly inconsistent.
But his first step, body control, and touch around the paint are superb. His learning curve is also extremely high. His defensive rotations and movement without the ball last year were as good as I've seen from a 19 year old rookie. He's very smart (both in IQ and basketball IQ), and is really developing quickly, hustles, and last year really did a good job of playing within himself. I wouldn't be surprised if in 2009-2010 he's the Sixers second best player. Not at all. His deficiencies are correctable with work, and he seems to have the work ethic to improve. He'll be a good one.