I'm now starting to like Vonleh a bit more than Exum. I think he's going to be hard to guard. He has the jumper, a pretty good first step, and a strong finish at the rim with pretty elite length. He's going to score on 3s and 4s.
Depends who you project them to be. If you're projecting Vonleh as an Aldridge type talent (his jumper is just un-guardable), then that's raised the bar pretty high.
On the other hand, if you're projecting Exum to have a Kobe/Jordan-esque type talent, then all bets are off IMO.