I have had excellent service from this vehicle in its' first 25,000 miles. I'm averaging about 14.9 mpg. On a long highway run it will go to 16mpg. I have had two minor issues fixed under warranty. Exhaust resonance, and a steering wheel "clunk". Both taken care of. I have 3 boys and we all go camping a lot. It hardly even knows it is pulling a camper and everyone has plenty of room. Rear seat passengers have their own heat and a/c vents for comfort. The ride smooths out once the truck is loaded a bit so the camping trips are a real pleasure.
When I bought this truck, it was for the purpose of pulling a 5th wheel RV and an enclosed snowmobile trailer. Most all towing would be in the mountains. I have alway driven GM trucks, so I was already use to the body style and interior, both of which I love. However, this is my first GMC. Ride is good for a 3/4 ton, power was good, although I knew I could better it later. Has the typical piston slap of this era of Vortec engines, but has not caused any problems. I run Amsoil synthetic oil, I change the filter every 5000 and the oil every 10,000.
I really only have one gripe about the best truck I've ever owned and that's this: GM will not recall a 6.0 for a oil pump seal that causes the oil to airiate and leaves the owner with the impression that there's a collapsed lifter. Anyone else hear that annoying ticking? Check the GM service records and you'll see that its a 300.00 fix/maybe kind of thing.