I don't really dislike any of them. If I have to pick, Marshall is coach I dislike the most simply because he is a rival. He's also the coach I admire the most because of the way he turned two programs around. His presence at WSU has been great for the Valley, and I hope he sticks around.
Muller was on the Dean's List every year in Normal, so it makes sense that he holds his players to high standards. I got the impression a lot of his players didn't handle it well, and that may have factored a bit into a few of their several transfers. If not the most disliked coach in the valley, I think he might be the most disliked among his own players.