I'm a little late to the game, but I'll chime in to say I'm really happy with our '16 3500 Big Horn. I've only got 4500 miles on it so far, but 3000 of those were dragging a roughly 12K, 38' fiver through the Black Hills, to Yellowstone NP, and to Glacier NP. Didn't find a grade that caused any stress, up or down, despite only having the 3.42. I'd have to pull my numbers out again, but I think I averaged somewhere around 11.2mpg for the trip. I was happy, considering the elevation changes and some headwinds. It was a far easier drive than I expected.
As long as reliability is as good as the performance, I'll plan on keeping this one for a long time.
