We paid over $65,000 for this beast and was happy with it for a while. Tranny slipped and brakes slipped none of which the dealer could duplicate. We serviced it regularly and waxed it every 6 months and garaged daily. In August of 2014, the Denali had to be outside at night but was waxed in that month. December I noticed that the paint was getting weird on the top and front engine cover. I tried to wax it off to no avail and reported it to the dealer. He gave me the GMC rep's name and number but never heard back from my message to him. It is now March and when I finally spoke to him in February, he said he would report it but it would not likely be taken care of. I will not buy GMC.
This SUV has been a disappointment from the start. Random "service Stabilitrack" warning turning off on it's own. The dealer could not dup it or find it on the diagnostics, but it would return all the time.
The big one was some MAJOR engine trouble with a collapsed intake valve, of course right after the power-train warranty expired.
Then some minor issues such as the cheap plastic plunger broke on the gas tank cover causing the cover to get stuck closed. One of the Bose speakers has the cone delaminated. Leaking windshield wiper basin would drain all the fluids in a day. The batteries seem to deplete quicker than any other SUV I've had. Has the feel of a cheaply made SUV.