In my mind it should be between Teddy, Clowney, and Mack. In reality I think it's between Teddy, Clowney, Mack, Bortles, and trading down (I guess that would be a cop out answer).
I'm not sure who I like more between Clowney and Mack. I think Clowney is the better talent but as of now Mack is the better player. I think Clowney is the top talent in the draft and at worst the the 2nd or 3rd best player in the draft but all of this once in a decade/generation prospect stuff is hyperbole. Dude wouldn't even be the best dlineman on the team and Watt just came out a few years ago. I'm not sure he's a dip and bend guy on the edge either. I really like him though. Mack can play multiple lber positions and is a 3 down type of talent.
I voted Teddy. I'm not sure what to make of Bortles "rising" and Teddy "falling". I think in reality these guys don't really fluctuate as much as the media likes to pretend they do. In every Bill O'Brien interview that I've seen where he speaks about quarterbacks (both before and after he was hired) it sounds like he's reading off of a Bridgewater scouting report. Granted we have no clue about what happens during private workouts and meetings but if O'Brien is going to put his money (or McNair's money) where his mouth is then Bridgewater will be the pick. As far as upside, I look at quarterbacks differently than the other positions. Once a qb has checked all of the physical boxes required to play in the league (imo all of the "top 3" qbs do) a quarterback's upside is mostly tied to his football iq. People can talk about wow factors all they want but out of Peyton, Rodgers, Brees, and Brady the only "wow" worthy physical traits for any of them is simply Brady and Peyton's height. People can debate all they want about what tools give Wilson, Kaep, Luck, Cam, Cornball the chance to be elite one day but the reality is the guy(s) that will be at the top of the hill will do so by beating teams with what is between their ears. In saying that I think Bridgewater has the most upside of the qbs in this class.