The cummins is a better engine.
The Ford truck (take the engine out of the picture) is better than the Dodge in every area I can think of.
Best engine is the Dodge. Best "truck" is the Ford.
Keep in mind the tranny is the weak link in both trucks NOT the engines.
I would buy the Ford. It is way higher quality than a Dodge pick up IMO. I have sold both and far more problems with the dodge trans than in the ford.
Very few people with diesel trucks NEED diesel trucks. Be careful not to buy on "cool factor" because diesel trucks are more expensive to operate across the entire life of the truck. Saving the extra cost paid for the diesel option in fuel savings is also a farce.
I am sure someone will chime in and tell me how they have actually saved so much in fuel over years but major construction companies have found that not to be the case. At least not enough savings to overcome the higher purchase price and higher maintenance.
Also consider the idea that diesel production for light trucks will be the first fuel sacrificed in the event of a shortage. This a real possibility in the next few years.