My OEM Firestones did great as well. Pulled them off at 50k and they all had 7-8/32nds left on them. DT manager asked why I was replacing them and told him I always take tires off by 50k, usually 40k. Told me they would take $200 off the selling price of the replacements I was putting on. They were an excellent set of tires for me. I replaced them with Michelin Defender LTX M/S which are the quietest, smoothest truck tires I've ever owned I believe. They aren't an aggressive off road tire but that's not what you want for towing anyway IMO. They are excellent in rain, dirt, sand and mud....considering that they're not full bore off road tires.
As far as off road capability and noise, the more off road capable the tire is the noisier it is as I'm sure you know. To me there is a trade off when trying to get max off road traction, especially when trying to use the same tires for towing. The more aggressive the tire the louder it gets; some that aren't very aggressive are loud. Off road tires also tend to ride hard due to rubber compounds and large slabs of rubber or they are soft for grip and wear out by the time you drive around the block a couple of times
. I've owned Nitto, Toyo, Bridgestone, Firestone, ProComp, BFG (all kinds), Goodyear (all kinds), Yokohama, Dick Cepek, Michelin (all kinds) and others. I've pretty much determined that Michelin is the way to go for me. Good luck in your search.