If you want Jazz to succeed at a high level you better hope both develop into at least above average starters. I think both of them can.I am not picking one over other. It's just an numeric statistical fact to those who argue that Exum is more athletic.
They are both very young and plenty of time to greatly improve.
Mitchell is a little more advanced and developed coming into the NBA. Exum was much more raw.
I think both can get to that borderline all star level. I'm hoping one can or both can exceed that. They both have potential to but who knows where they will get.