I have a 2008 F250 crewcab super duty, 5.4l 3.73 rear end and 5 speed "torque shift" auto transmission. It has been great. I am not towing as big a trailer as many here - 4500lb 21' travel trailer.
To "be happy" with a tow vehicle is different for every person. When I come to larger hills I expect the truck to downshift and revs to increase. On flat ground the truck shifts into overdrive and cruises. I can get 10mpg towing depending on hills. Empty on the highway it is almost always 15.4 mpg calculated by me - the "mileage computer" on the truck almost always reads .5 mpg better, lol! I have no idea why.
People I know with the V-10 love them for towing and work, but try to avoid driving them "around town" unless they have to due to the fuel mileage.
I don't know if this helps! Good luck.