A diesel will certainly give you more torque (pulling power) and better mileage than a gasser. I change the oil when every my onboard sensor tells me to which is about every 7K miles. All the diesel fuel I've found in the last couple of years is the same now, and will work well in any diesel engine. This 2013 diesel is the first one I've ever owned, and I certainly won't go back to gas.
Now the big issue. The 6.0 Ford diesel has a history of serious failures and very expensive repairs. My son has one, and he's had to replace 6 of the 8 injectors which are very expensive. Do your homework on this engine, and make sure you get the history on the work that was done on this particular vehicle.
Jim