The power and acceleration are unbelievable. Handling is very good for a pickup. I only have 1000 miles on it so far, but very satisfied overall. I previously had an '01 Tahoe with the 5.3 engine, and the Sierra Denali with the 6.0 is getting slightly better mileage (if I keep a light foot on the gas). For some reason I could never average better than 13.5 with the Tahoe around town, and am getting just under 14 with the Sierra. I think the ethanol fuels around here are partly to blame for lower mileage. The tonneau cover that came with the truck is OK, but I think an Access brand cover would be better - easier to roll up than the GMC model. The all wheel drive is very smooth.
All-wheel drive, great sounding stereo, XM Radio, rear DVD system,
Add tire pressure monitoring system and side curtain air bags. Additional colors should be offered (only available in black, white, and silver).