I have one and it is a great Truck. It is the first Ford I ever owned and it tows great. I have the Banks Stinger Plus System on it and I get about 16.5 around town. I ordered it with all of the towing stuff so the gearing is high.
I tow my Formula 382 with it ~14,500 lbs with the trailer and I smokes up hills, the Dually is totally stable towing in high winds and when being passed by a Semi!
I can pass my friends with similar weight boats on any grade..one has a Freightliner FL60 and the other a Kodiak with the Cat motor.
I also have the BUC barke on it..similar to a jake breake. It is great for long downhills you never need to use truck or trailer brakes hardly.