I run Toyo Open Country A/T's on my Bronco. They do well for me, and clean out pretty well considering they are an all terrain tire.

My Dad's had Les Schwab Mud Terrain SXT's, Toyo M-55's, and is now running Cooper Discoverer ATR's on his '00 F250 now since it's no longer a farm truck.

The SXT's did good in the snow and mud but sucked in the rain and provided no forward momentum if you were on ice. The M-55's were just as good in mud and snow, better in the rain, and weren't as noisy. Pretty much a better all around tire than the SXT and didn't wear out as quickly.

Both the SXTs and M-55s were M+S rated so they are considered a "traction device" when travelling the pass. Doesn't mean you won't have to chain up though.

He just picked up the ATRs a couple months ago and is happy with them so far. He gets better fuel mileage, they ride nicer and are much quieter. Don't know how they do in foul weather yet, but will find out soon enough!

Hope this helps you decide the best fit for your truck.