The new truck is such an improvment in so many categories. Beautiful highway cruiser. We test drove a '21 Denali 6.2 and were really impressed with the ride and truck. We had a 2017 Denali XL 6.2 which got pretty good mileage. Saw 24 mpg driving nice on hwy often, routinely 21-22 mpg. That generation the 6.2 actually got better mileage than the 5.3. BUT the 2021 mileage was pretty bad. Then we reneted a Suburban for a month w 5.3. Could not wrap my head around that the mileage went down on a new vehicle? Then heard the Denali 6.2 was much worse and took premium also as we know. Dealbreaker for me. Tried to find a 3.0 Denali to no avail at the time, then Covid and the insane market change. So found a 2021 Sierra Denali w/ the 3.0 and the ultimate package and have fallen in love with this motor! Mileage is everything you hear...great. Between the lifters and the mileage, its not even a consideration till we find a deal on a Yukon XL with the 3.0.