I went with the 6.8L and 4:30 gearing. The 6.8 has a little less power than the 7.3 but the way it's matched to the tranny and gearing I'm very happy. I live above 7000ft and do all my towing between 5 and 8000 ft. With the 10 speed transmission behind these modern V8 engines there is no problem handling loads up to 12,000 lb. Towing my 6k camper or a 3 horse trailer loaded full is not a problem. Of coarse you cannot overcome physics at altitude but that's were gearing and leveraging the engines torque is critical for a naturally aspirated V8 gasser. I put alot of value on payload and stability with a horse trailer therefore a 3/4 ton truck suites my needs better than a half ton. 15 to 16 mpg on hwy at 70 mph. Fords powertrain programming is excellent. If you're a guy that has to run hard when towing well above the speed limit then by all means go with a diesel. Plenty of youtube videos on the 7.3l towing.
I have a 21' 7.3 with 4.30 gearing. I made the switch to gas after 3 diesel trucks and I wont be going back to a diesel unless I need to tow over 18k. I live at 5,500 and tow 6-10,000. This summer I towed 14k through wyoming, Montana, Idaho, and Oregon passes and never needed more power or wished for the power of a diesel.
