I have a 2015 Denali XL that I bought new in 14. There a quite a few things that I like about it, but the bad things outweigh the good. 1...When using the cruise control on the highway or interstate, the vehicle will actually activates the brakes to slow down. It has a tendency to over accelerate down hill then brake and then it forgets to accelerate on the uphill until it looses 4-5 MPH, so it will vary from the "set speed" 4-5 too high and 4-5 too low. Drives me nuts. The dealership says it is within acceptable range and there is nothing they can do. 2...The brakes (all 4 corners) had to be replaced at 80,000 miles. 80% of my driving is highway / interstate and with previous vehicles, I'm usually at least double that but with this thing accelerating and then braking (cruise control), it is always working the brakes. 3...I had to replace all 4 shocks at 80,000 miles at a cost of over $3,000.00. This would be easier to accept if the shocks made the truck ride better, but it rides like a lumber wagon.
All in all, I love the practicality of the vehicle, but it is very irritating to drive.