I have recently purchased my second diesel truck. I really would have a hard time going back to a gas truck. I probably would if I were buying a new truck. From what I understand, the newer diesel trucks have an exceptional number of very expensive to meet current smog requirements.
When discussing Ford, GM, or Dodge trucks, it is so typical for folks to be obsessed with a particular brand. Brand loyalty can really compromise ones point of view. It is great that some people have had no issues with the Ford 6.0. As I recall, Ford had issues with it and sued International. I do not know the particulars. Fords may have some good engines, but I really do not think the 6.0 is one of them.
I encourage the OP to read the different diesel Forums. I will be so bold as to say each of the three have their weak points, but with upgrades can be made bullet proof.
Wayne