The downside that some will point to would be sharing the spotlight with the Hawks for two rounds. But who wouldn't feel better about playing them than Gonzaga? Do we really think Georges would let us lose that game? No way.
The main downside I would see to a Sweet 16 game against Iowa is if (a big if) we were to lose. Imagine how bad that would be. Yikes. That's a loss we'd never live down, and would hear about from Hawk fans until the end of time. Other than that...yeah, sure. ;-)
There's not that much upside to playing a team that we beat by double digits again in the tourney. You lose that, and you have a sour taste in your mouth for the rest of your life.
If you lose to almost any other team in the Sweet 16, you look back fondly at this season for the remainder of your years.