We just picked up our 2020 Sierra 1500 Denali diesel today. For the 70 miles we've driven it, we are happy with the purchase. I really wanted the SLT with X31, but when we drove it and then the Denali with Ultimate (both diesels) my wife really liked the ride on the Denali better. Since she will drive it more than myself, I felt that was the way to go. This will be our 3 diesel in the family with the other 2 being Audi's. For some reason, I really like them (along with the vastly superior fuel economy).