X's and O's? Brad.
Relating to players, and getting people to compete at higher levels? Ime.
I think overall Brad is probably a better coach, but if you can't get your players to execute at the level they are capable of, then that doesn't mean as much. Regardless of if it is fair or not, Ime has gotten these guys (to this point) to play very hard.
We'll see what the playoffs bring for Ime though.