I witnessed a set of Longtrails offroad in sand and was very surprized by their performance. They have the top rating per Consumer Reports but I knew that was for mostly street use and looking at the tread I wouldn't have expected them to do much offroad.
However, on the Slabs Run some of us Texans went on last month, a Tahoe joined our group sporting a new set of BFG Longtrails. The area was a riverbed of white sand, very deep, like loose dry beach sand. A friend in a 2wd that followed me down only made it about fifteen yards before sinking up to his axles in the stuff.
That Tahoe kept its own with us for the entire weekend and had no problems struggling through that deep sand at all. I was very surprized and impressed with the performance of those tires. Had I not witnessed that, I would have suggested yeah Longtrails have the highest rating but that's for grocery getters. But I have to admit that a look at their tread does not tell the story of how well they perform on the trail. It doesn't make sense to me, but I SAW them work, and I was impressed.