He's a smart, technically proficient player.
He plays bigger than he is...the 36 Combine lifts show up on the field. Everybody underestimated how well he honed his craft at the college level. I don't think you'll ever hear McCarthy b*tch about his "pad level"

...the guy knows leverage. His feet and hands are just the way you draw it up. Very good awareness.
He's a very good pass blocker, but I think the highlights he's brought to this season are the frequency with which holes are being opened up inside the tackles as we've progressed through the season.
It's generally under appreciated how much offensive line play is a team game, particularly in a zone blocking scheme. Executing a block is one thing, but knowing where to go and who to block based on what the guys on either side are going to do is where it starts.
Though he's a fully formed player, there's probably a bit more upside. Another under appreciated aspect of the game in general is the value of a trip or two around the Division. Learning the strengths, weaknesses and tendencies of the guys on the other side of the ball is no small thing for 6 games out of the year. There's simply no educational substitute for snaps in money games.
A pleasant surprise, to be sure.