I just put a set of Cooper AT3s on my truck a few weeks ago. I really, really like these tires. They handle very well on the road, the ride is quiet and smooth. I've had them in loose gravel and wet fields, but not much mud. I don't have any complaints with them right now, and would recommend them. Traction in the wet grass of the field (uphill) was good. I haven't had the chance to tow with them or drive on wet roads yet.
The only thing I noticed was it seems like they used some awfully big wheel weights to balance them. That could just be the shop I used, heck for all I know my wheels could be a little tweaked. In any case, I'm very happy with the tires.
I ran some Yokahama tires on an old F-350 dump truck I had, but not the ATS.