In a few weeks I'll be picking up my last new diesel, Ram 2500 4x4 Laramie. My next TT and truck combo will be lighter and smaller, a 1/2 ton with a TT <5000. With what I tow I could have gone gas 6.4 but the diesel puts down the miles much easier over the hills. BTW, my present 03 Ram was built in Mexico and has been the best vehicle I have ever owned.
Gas engines that deliver these HP and MPG #s fill a nice void in the market. The 5.7 Dodge, 6.0 Chevy and 5.4 Ford are under-powered for an 8500lb TT (a common loaded weight). The bigger engines (most discontinued) can do the job but get terrible MPG. The diesel is great but the initial purchase cost is out of a lot of people's budgets.
I'm in a Duramax now and am happy but as it ages and I think of my next truck some of the new gas offerings have certainly caught my eye.