My players hates Controllers of all sorts.
They already faced a TPK, basicly by the hands of an Orc Eye of Gruumsh (and several other stuff), which kept lowering their AC by 4 every turn (minor action too) making them easy targets for the other orcs..
Now, when they see a "mage" type sort of critter, it quickly becomes their priority target.
Soldiers are kinda hard too, but when there's one, it's easier to just ignore him and take care of the rest of the critters, then alone, not so tough.