Yes, what engines are we talking about here? haha.

I like my 06 5.9 with a generic tuner, I'm happy with the power available, and I'm able to get about 20 mpg on the highway. Not bad if you ask me considering its a 7500+ lb truck empty, it's lifted, 4x4 drivetrain, and riding on big heavy 35" mud tires.

My mom just bought a '15 6.7 to tow her 5th wheel camper trailer with. She's getting around 21-22 mpg on the highway empty, so I think whatever issues they ran into when the 6.7 came out and everything got DEF filters etc. have been resolved/corrected. Her truck has gauges that I had to install aftermarket--Trans temp, boost gauge, etc. (Don't remember if a pyro was one of the options or not)