Tow rating and air bags are great marketing talking points but not all that relevant when comparing how the two trucks will perform and their durability. Ram has a much stronger frame (as strong as the ones on the GM trucks) and Ford transmissions have been more reliable than those on the Dodge/Ram trucks over the years.
More relevant are the J2807 test like the ones done by Car and Driver in 2012 and by Mrtrailer.com in 2011 with actually heavy trailer loads and trucks driven up and down steep grades and through obstacle courses and braking with and without the trailer's brakes. Even subtle aspects like the ability of the trucks to control downhill speeds varied significantly between the GM, Ford, and Ram trucks based on the integration of the engine, transmission, and exhaust brake components.
Oddly enough none of the truck magazines, even the ones dedicated to diesel trucks, have bothered to come up to speed on the SAE J2807 which is pretty pathetic journalism on their part.