We bought our 2018 new and I am very impressed with the drive train! I have gotten 58 mpg highway and normally get 35-43 mpg in city driving although The Twin Cities in Minnesota do have lots of freeway driving. Acceleration is good enough and so far at 42,000 miles very little in service problems. I did find out you do NOT want to idle the engine for more than 5 to 10 minutes. Even in our cold weather I just get in and turn on the seat heat and the steering wheel heat and the max defrost(electric boost heat) and then drive away! we do regular trips to visit family and it gives really great hi way mpg. Keeps telling me I can drive 800 miles or more on a tank of fuel! I do have one caution. Research revealed that you need to add one quart of Mobil 1 ESPx2 0w-20 to each oil change to extend the timing chain life due too it's position at the back of the engine next to the firewall. This will extend the life of the engine to 100,000 before any timing chain problems will occur. The only way to service it is to take the entire engine transmission unit out of the car. If it needs that service just have them do Everything it needs!
This is my 6th GM diesel vehicle and the only one I am paying the dealer to service because I got tired of getting under the vehicles. I am very impressed with all the diesels I have owned. I just read the owners manual and ask questions of the mechanics that work on them so I can learn the best way to get trouble free driving.