I had a 2011 F350 and now a 2012 Ram 3500 dually. The Ford pulls a lot harder, and I personally think the Ford transmission is the best of the Big 3. The Ram exhaust brake is much better than the Ford. The ford rode better loaded, but the Ram rides better empty (but I am comparing to my dually, not a 2500). My Ford averaged approx. 4 MPG better fuel mileage...and that's a lot.
Overall, I think the Ford is cheaper to operate, but the Ram will be cheaper on normal repairs when the trucks reach higher mileage. Water pump on the Ram is dirt cheap and you can do it between your morning coffee and leaving for work....simple. DEF is a good thing, don't be scared of it.
Either truck should serve you well.
