Which tires to buy?

[Bhplumber]

I have been researching tires for awhile. I am currently running Toyo MT 37x13.50x17. I am going up to 20" wheels and really would like to get a good high mileage AT. I really am a fan of the BFG AT. I havent had much luck with coming up with options. My toyos are ok but they do have alot of drag on the beast. I am looking at Hankook Mt, Mickey Thompson AT in a 38x15.50x20, and the Toyo Mt. anyone have any experience with the Mickey's? Do you think the 15.50 would cause alot of drag and not gain me anything over the toyos. I would prefer a 13.50 vs the 15.50. any input would be great. I know almost everyone says TOYO MT but I put about 35-40K on my truck per year so need something with nice road manners.