I have the MT 450 on the back of my CR265 right now. Don't like it. It skates too much. But I'm riding hard pack desert with pea sized gravel and tons of dust on most of it, with lose rocky climbs inbetween. I've heard it does pretty good on an mx track.
If he's got any MT 44 fronts down there for 40% off, grab um all! It hooks up and stays put under all conditions. Best front tire I've ever used. But they don't last..out here anyway. But I'll still keep using them.