As I work in the industry, I can advise you to stay away from any Ford diesel that isn't a 7.3. My boss just bought a house in Mexico off the 6.0, 6.4 and the 6.7 doesn't sound any better so far. The dodges are pretty bullet proof. The 5.9 will go forever! The 6.7 seems pretty decent but the factory clutches are pretty weak. The chevy duramax is very solid, we've not done any major repairs on any yet. If you drive easy you can get 20-22 mpg with most diesels depending on gear ratios etc. But these idiots who say they chipped their truck and now get 26-30mpg are just blowing smoke.