I have the procomp muds. I unfortunately haven't been able to find any mud to test them in, and then my truck broke when all the rain came. That sucks, but they work great in other stuff.
Rockcrawling-Great traction, didn't have any problems at all getting stuck on boulders in joshua tree. I aired down to 18-20psi and they molded around the rocks and pulled right through the tough sections.
Sand-I air down to 20psi on the sand and it works just fine. A lot of people say mud tires suck in the sand, but they aren't too bad. Sure an a/t would be better, but the muds still work.
Loose stuff(gravel, dirt)-Work excellent. I was up against Ken Cooke with his bfg at ko's in the same loose spot in joshua tree and he had to get strapped out, when my truck was able to take hold and pull right out. (I'm not braggin Ken! just statin the facts
)
treadlife-I haven't had them for that long, maybe 5 months, but they seem to be holding up ok. An allterrain will last longer because of the harder compound, but I believe that if you go offroad a lot and are peticular about grip and tire performance, aaaannnd don't want to spend 190 per tire on some mt baja claws, then you should go with the procomp or bfg mt's. But, if you are more the daily driverish kinda guy who goes offroad once in a while type thing, then you should probly stick with an all terrain for better treadlife. All terrains do still do an excellent job offroad. And don't get me wrong, its not like I'm offroad every day either. I mostly drive on the road and go offroad when I can.
Oh and chicks dig the muds
