the biggest thing for me is just that he wasn't recruited as Tom Brady 2.0 by anyone. In RR's mind (from what I know of his system) he was recruited to scare defenses with his running enough to open up wide open passes, which were the passes he was expected to hit. When called on to do this, he's done a pretty good job.
"He makes it really easy on you as a coach because he has tremendous football instincts," Michigan tight ends coach Jay Harbaugh said. "Things come really naturally to him. He doesn't have to see things too many times. He has a good sense for how things should look and feel, and he's a tough, physical guy."