You don't know squat about diesels if you think Ford has the best diesel. The Cummins is the best by far and I don't care if the Ford has slightly more power or not. Ford has had problems with their diesels on and off for quite some time. Yes, the latest version is pretty good, but I still don't fully trust them.
The Dodge is basically a smaller version of a semi engine. Cummins knows what they are doing. Look at the Cummins in Dodge trucks and the engine design overall. That's a monster, and it was built to last.
Did you know that the Dodge has about 2X the main bearing surface area as the Ford? Which engine do you think will last longer?
Back when Dodge first put the Cummins in pickups, I know a big farm that bought about 4 trucks, all with the 5 speed. The trucks were still running strong after 500,000 miles, and they weren't easy miles. They were used to pull trailers, stuck tractors, hauling heavy stuff, etc. They were used and abused, but it didn't matter.