I ran BFG AT 275/70 r 16 for 2 years. Sold them to a pal of mine. just swopped them for BFG AT 265/75 bit skinnier, bit taller (they look noticeably taller), more down force on tread blocks so better grip on rocky stuff - plus when you deflate tread gets longer so more grip. BFG dont make them in AT but it they had would have gone for 255/85.
can feel truck is a bit slower on pick up, a bit more brake pressure needed to stop, and with the bigger sidewalls its not as crisp through the bends, slightly softer ride. BUT well pleased with them, very well pleased.
If its a "downside" the truck is no longer skirt friendly for my friends when they get in.