No running expert here, but I just picked up a pair of Asics and they REALLY helped out on my left knee which I dislocated about 6 years ago and tends to get sore easily. Also have helped out with shin splints that I would get while running, but go down fairly quick.
My girl tried to get me to do the tough mudder (shes a running machine!), but definitely not ready for that one yet
I did the Warrior Dash and Dirty 6 Mud Run here in Arizona, absolute blast. By next year I should be ready for Tough Mudder!