I have heard good things about the new MT/Rs, but don't personally know anyone using them.
I am running Mastercraft Courser CTs and I love 'em - pretty quiet on the street and they seem to handle what little mud I've thrown at them just fine. If you are looking for something less pavement oriented check out the Cooper STTs. They get tons of great reviews and they are priced well.
My CTs:
Cooper STTs:
- Justin