I like it. I read as much for reviews as I could find before I picked it up and it meets or exceeds any postive review I have read. Very reliable. The only thing I'm bumming out on is that I had to buy the only model you can't change tire size on without (warranty issues) getting a tuner or such and that's coming. I'm happy with it other than the tire size from GM.
The four wheel on the fly is critical for me. The awesome power this engine generates is amazing. The ride quality will rival expensive luxury cars. People ask me all the time if it is really a diesel because it is so quiet. They are also impressed with the acceleration, ride quality, and quietness when they ride with me. I will buy another GMC diesel when this one is worn out...in about 20 years or 350,000 miles.
The leather seats are comfortable and easy to keep up. It makes getting in and out much easier too. I like everything about this truck.
The only things I would change about this vehicle is the fender well size to accept bigger tires without doing a 2" lift. I use a Hypertech programmer to increase performance and mileage that could, and should, be programmed at the factory.
This truck is a replacement for my stolen '03 F-250 Powerstroke. After 11 months of trying to like this truck, I would take my 4 year old Ford back in a heartbeat. The much-touted Allison tranny screams like a banshee when I am towing up the long steep mountain roads in NM and AZ. It's clunky and jerky. Trips to the dealership have found nothing wrong. The mileage runs around a dismal 13 mpg vs. 18+ for the '03 Ford. This heavy duty truck came with puny 6 ply road tires on it, which I think is ridiculous. I resent having to shell out for 10 ply Michelin all terrain tires at 6000 miles because the truck tires couldn't get a grip on our muddy winter roads, even in 4WD.
The interior design is great, which I find to be superior to both the new Fords and even my husband's brand new '08 Tundra. It is well thought-out and convenient, with ample stowing and extra room for overflow things like saddles, horse feed and very large dogs.
Back to the design board, fellas. This thing is ugly. Put some decent and bigger tires on it. Not sure about the Allison tranny. Maybe I got a lemon?
I drove the '08 Ford and '07 Dodge and none come close to the GMC. This is my second GM truck. I'm very hapy with it. The power is great. The only draw back is the mileage, but I was expecting that from a big truck.
Traded my 2006 Sierra 2500HD 6.0 V8 for the Allison/Duramax. Super truck. I was amazed how much better the ride is in the 2007 Sierra Classic. Duramax/Allison combo a real delight to tow with. The Allison 6 speed works incredibly well with the Duramax to couple all of that torque to the ground as well as assisting in stopping the whole load. Torque comes in at about 1500 RPMS and this thing launches like a rocket. Great fit and finish. I researched all other diesels and I'm happy I stuck with GMC.
Duramax/Allison combo. Ride and handling excellent. Anti-lock braking. Heavy-duty construction.