All this talk of who is the fastest to the top of mt Everest cracks me up!
I know for a fact as I just made the switch from a ford v-10 coach to a 300 cummins diesel that the diesel is just simply smoother and more efficient than the gas.
Yes the gas is a very capable engine but something I can't ignore is the fact the both were pulling a 4600lb jeep for the last 3-4 years and on the gas I averaged just about 6.6 mpg and with the diesel so far 11.8. Huge difference! Yes I hand calculate and keep logs. This is also traveling mainly up and down the relatively flat east coast. We couldn't even make a round trip from Philadelphia to the finger lakes of ny with those small hills on one tank of gas. Just under 300 miles on a 55 gallon tank, not good!
My gasser weighed around 20k gcwr and the diesel just weighed in at a hair below 28k gcwr.