Cornbread for sure... not Coldiron.. I used to think he was the best but he tends to have his favorite coaches and spends a lot of time debating the calls with them.
Sandlin does well.
My three would be Samdlin, Knollman and Cornbread..
How about changing the refs from region to region every year. I think when they have too close of a relationship with some of the Coaches is is perceived as favortism.