When I watched his highlight tape on SI.com, one thing I noticed was the fact that he really does have a quick release, not just in the throw itself but in the mechanics. In watching a lot of QB's I've noticed that they always seem to do that pat with the ball right before they throw it, and in turn it can cost the QB a second or two in delievering the football, which we all know is critical time at the NFL level. In some cases it can also tip off the safety and lead to a pick. Colt on the other hand has a case of see window hit window, which should help him at the NFL level.
The sidearm release worries me a little though, but hopefully Z-Man can do with Brennan what the Texans failed to do with another sidearm QB in Carr.
SI.com - NFL Draft 2008