At 6' 2" Hamilton is a big target on the outside. He spent his first three years at Arkansas buried in the depth chart behind a trio of excellent wide outs, but in his senior season, he become the focal point of the passing offense. Even before when he was lower on the depth chart he still managed some breakout moments. See below at the 1:15 mark:
You can see one of his strengths. YAC. While one of his legendary moments at Arkansas featured a colossal mistake by an LSU safety, you can see his speed as he breaks down the field, finds his blockers, and avoids the would be tacklers.
Hamilton had his best season as a senior and gouged defenses with big yardage on his crossing routes. For his height you don't expect him to burst out of his cuts on the Wes Welker type underneath routes, but Tyler Wilson was able to build a lot of confidence that he'd be open on those routes over the course of the season as they connected 90 times. Hamilton can position himself to make the play even if it's not the best pass over the middle and then earn some extra yards with a strong stiff arm and a quick burst after the catch.
He's also been very reliable. Hamilton is Arkansas' career and single season receptions leader and single season receiving yardage leader, and set the SEC record for receiving yards in a game for his 303-yard performance against Rutgers.
He never suffered any serious injuries during his Razorback career and tallied at least one reception in each of his last 34 Arkansas games dating back to September of his sophomore season.
The biggest complaint about Cobi Hamilton has been his hands. They are on the small side. However, if you talk to Arkansas fans, they can recall Bobby Petrino and staff raving and saying he had the best hands of all their wide receivers when he was a freshman and sophomore. With the drops that we've seen on the collegiate level, it may have been either focus or trying too hard to do too much. With a reputation for big YAC you often see the biggest problem with those wide receivers is a failure to lock the ball in before making the next move. Hamilton works best if he can be targeted directly in the chest, which may be more difficult to expect on the next level.
Cobi Hamilton also doesn't have the big leaping ability you'd like out of a 6' 2" receiver. With his speed and route running, you'd like to be able to see him take an outside post and out-jump the smaller cornerbacks, but when you combine short hops and small hands you won't see him winning the one on one battles for jump balls on the outside.
Cobi Hamilton's production and physical measurements speak for themselves. As the main target on a bad SEC team last season, he still ranked 5th in the nation in receiving yards.
His route running and size will be a major asset in the NFL. If he can continue to churn up yards after the catch, he'll be a nightmare for NFL cornerbacks. He's been projected all over the board, but some NFL team is going to get a very reliable and consistent receiver.