The Duramax 6L diesel is more than I expected. Not only is it quit, it rides like a dream. This engine also has the power to move anything I hook up to. The layout of the interior is excelent, everything right where I can reach it. This was a very good buy for me.
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.