If I had it all to do over again (and I might?), I'd snag a Super Duty 7.3L and just make it a good truck with a little $. To me, they have enough power to pull fine, are pretty comfy and had less maint. issues than the Dodge. Just my experience, I'm sure there will be some Dodge guys defending their trucks and their F*rd experiences will echo my Dodge experiences.
Both have unit bearings and they are maint. prone. Both have questionable automatic transmissions that cost similar to rebuild. Both can build respectable (or insane) power with some moderate mods. I just think the TRUCK is better for the F*rd if you can get past their stupid door lock switches and power window switches. The interior and the body of the Ford will hold up over time better in my opinion. The Cummins might make it to 500k miles, but your truck will literally be duct taped and baling wired together. I have a '96 F250 that's been USED with 260k and it's still fairly solid.