Not sure about the M/T's, but I've never gotten more than 35K out of three sets of Open Country A/T's (285/75/16). Rotated religiously every 5K and checked pressures weekly. No towing or offroad. They were very quiet and good on wet pavement, they just didn't last. (50K wear warranty)
Why was I so stupid to keep running them? Dealer treated me VERY generously on adjustment. Toyo recently came out with a 285 in the M-55, so I've got ~10K on them. They're 10 ply and supposed to wear much better. They do sing quite a bit, but not enough to discourage me from considering them again if they end up wearing well. Pretty spendy, tho.