Nice looking truck! I had 2 different (both 7.3) Ford diesels over the last 15 years or so and though I liked them I couldn't bring myself to buy another what with engine problems Ford has had with the newer ones. Don't even get me started on the tranny's.
I love my GMC 3500 with the Duramax/Allison. It easily out-tows either of the Fords that I had, and both of them were not exactly stock. It handles my 13,000 lb. 5th wheel without complaint. So don't let the detractors who haven't driven the dmax/allison combo get you down.
Duallies are just bad-***! Only down side is buying new tires, and I hope you like hand washing. That is a lot of sheet metal!