A set of P-rated 265s AT3's were put on my dad's tahoe and for ride quality, traction, stopping, and general running around they've done great. Can't say for mileage, there's about 10k on them and don't appear to have considerably worn. Truck sees occasional tow duty up to ~4klbs, and has done fine.
I still yelled for him to put LT rated ones on, but what do I know.
I am considering a set of E range AT3s for my 3500 when the ST's have lived their life out. Currently at ~20k miles and LOTS of life left.