TFL Truck did the IKE pulling a 10k lb trailer in the 7.3, while they did it in roughly the same time going up the grade pulling a 30k lbs trailer in a F350 DRW with the 6.7 diesel. That's a HUGE difference in power considering the diesel was pulling an extra 20k lbs. Furthermore the mpg were roughly the same. Finally another noticeable difference was the diesel was far quieter going up the grade without the constant loud droning of the big block gasser. Going down the hill was also much easier with the advantage of the diesel having the exhaust brake.
At the end of the day, the decision seems to come down to whether it's worth it to you to spend roughly $8500 less for the gasser but suffer with more noise and a towing experience that's not as relaxing as the diesel.
