For 99% of users there will be no notable difference between the 3 engines. Very few people will ever haul enough to know the difference between 765 ft-lbs and 800 ft-lbs. I still like the cummins even if it doesn't have the power numbers there's a certain comfort factor to an I6 vs a V8 in a diesel.
Give dodge a year or two, I imagine the power figures will be increasing a bit and they are working on a 7 speed to put behind the cummins, that will put them right back in the running.
7 speed? Where did you hear that?