My rig had 22k miles on it when I bought it. Nitto's have maybe 25% tread left. That's not very good in my book. Definitely less than you got out of your BFG's. Also, they are D load rated, and they have a lot of sidewall flex, someone told me they aren't 3ply sidewalls like BFG's or Goodyear MTR's. I'm not a 100% on going BFG again, I have them on my Tacoma, and they have been good for that truck. I was reading in another thread that people seem to like the Cooper MTR's....so I might try them. Also, I can't find a BFG in an E load rating, so that might seal the deal for me....I think our SMB's need an E.
06 SMB V-10 E-350 4x4 RB-50
-and a quiver of fiberglass and polyurethane foam.