I have 20K on my Hummer H2's and BFG's. My tires still look like new, tread wear is minimal. I am anal about tire pressure, so they get checked often and are kept at 50#s front and rear. I tow heavy loads of 12K or more many times and no problems. Their weight rating is every bit as good as an E-rated tire, and truthfully the sidewalls may be softer but the difference to me is minimal. I did not like the stock tires whatsoever, they just did not seem right from day one. My fuel mileage did not change when I went to the BFG's, no gains-no losses. The best improvement I saw was in rpm's, they got into the sweet spot of 1900-2000 rpm at 65-75mph, brfore that I was running 2300-2400rpms's with the stock tires.
I experienced some pogo-ing and a little sway with the stock tires, but it was quickly answered by installing Bilstein shocks and Firestone air bags.
CD