If you're going to take a flier on someone in the middle rounds because they have the prototypical size and a live arm, I'd go with Crompton. I think he showed some very good things last year, especially late in the year. The (putting it mildly) inconsistency before that can't be overlooked, of course. You're always wary of a guy who takes that long to learn or only flourishes when a pro coach comes to town (like Quinn did after Weis showed up in ND). Those are warning signs. But Crompton does have the size and flashes the ability to make rare throws from an accuracy and arm strength perspective and those are things you can work with.
I never had the chance to watch Levi Brown play so I'm just going off this poorly made,
very cheesy video of his highlights from the Southern Miss game:
http://www.youtube.com/watch?v=q3pgLJdyBh0
He shows some good things there but also shows a make-one-read-and-if-it's-not-there-start-scrambling-around mentality, ala Roethlisberger. Sometimes it works for him but other times not and either way you'd don't like to see a quarterback with a) overly happy feet, or b) no confidence in his progressions. There aren't enough plays in that video to really see which it is. That being said, he clearly has all the tools from a size perspective and has a quick release and flashes good accuracy. The one throw where he stands in and fires down the gun barrel to the middle of the field, showing great anticipation and accuracy... what a play. That one makes you stand up.
Of course, like I said, I didn't get the opportunity to watch Troy play this year, so my impression is (also to put it mildly) incomplete from having pretty much just watched the one video.
If I remember correctly you have Brown as your #5 QB, Slimm. What's your read on him?