Its all a question of options. I too have been trying to figure how to solve my towing needs problem in the best way. I also have a current dodge truck, but in my case I have the shortest lightest Ram 1500 with 2wd 3.7 V6, 6 speed manual with 3.55 rear end and... open diff.
My current truck can barely get itself out the driveway if there is a little ice and that is while wearing new bridgestone blizaks. Towing, it is too short and even with an anti sway hitch it requires a lot of attention to stay in a single lane at the best of times. My HiLo trailer has a low center of gravity as well as low drag, but boy, that 5000lb has everything but the semi's passing me in the rockies (and the semis do pass me going downhill !!!)
My Ram has been extremely reliable. Nothing on it has failed or made a hiccup in all the time I have owned it. But the body is already developing rust stains at the bottom of the doors and the tailgate already has bubbling rust at the bottom of the tailgate (2004 truck). The one time I towed a "regular" 22ft camping trailer, I got no better than 10mpg and could barely get over 60mph.
I have looked around, and ruled out the Silverado/GMC's since I can't stand the front end styling nor the interiors. The duramaxes are rare enough that here in the Midwest the prices are above my mantelpiece. I don't care much for the exterior styling of the rams, but the interiors are not too bad, but the quality of the bodywork and the use of unplated steel means I probably will not buy one again. The rams with the Cummins command somewhat of a premium (there were less of them made than any of the others, after all).
I have taken a long hard look at the earlier than 2007 F250/F350's but it is getting very hard to find one with reasonable mileage. With the facelift in 2008, those models just tend to look OLD, so worse for future resale value. In conclusion, I decided to find a 2008 model F250/350 with the kind of specification I was after and it appears that a lot of commercial operators have traded these model years to get the 2011 model with its supposed better mileage (I can believe it). Since my budget will just not stretch to the 2011's, the least expensive is going to be the 2008's.
That was my decision and shortly I will be flying from Lansing to Houston to pick up my truck.