I bought a '16 with ~17,000 on it on Halloween. I've put about 5k on it since then. Averages 12 mpg, mostly around town. It'll do 15-16 mpg on a 55 mph highway. It will haul ass empty, and doesn't slow down much with 5k behind it. Can't say on heavier loads because they go behind a bigger truck.
My only real complaint is the variable displacement. It comes in and out at inopportune times and makes the truck feel like it shifts too much. Also, at certain load/RPM combos it's pretty loud in the cab.
I went with the Laramie with leather, and it's very comfortable and nice to drive. But as of now, my plan is to pay it off in 2 years and go back to diesel. Find one just out of warranty and delete it.