There is no best offroad tire, Dune guys may be partial to the bfg AT while mud guys like the boggers or ag tires. Comp buggy guys from out west on mid west may say krawlers are the shiz, and the guys who run muddy trails may say MTR or x terrains or tsl or whatever.
What do you want to wheel is the first question you need to answer.
However, I have had 33x12.5 Pro comp x-terrains, 31x10.5 bfg mud terrains and 36x12.5 TSL SX and I think the tsl sx was best offroad, but the x terrains are very very good as well.