Of the big 3 which do you consider most trouble free,i'm talking of the new models. I know it subjective
If you want to beat the hell out of it I'd go with Ford.
Highway driving I doubt it matters much.
I really like the 6.7 Powerstroke, it's been great for us. We have an '11 and a '15 both F350's with the 6.7 and they are good to go work pickups.
But that said they are both deleted and that makes them REALLY great.
Horse1 gave an excellent post on the potential issues you face with the emissions systems.
This time of year a pickup might run for 6-7 hours straight with a lot of that being low RPM use so it was a no-brainer to delete. And the pickups are both out of warranty so no risk.
If I had the desire to buy a new diesel it would be tempting to delete right off the bat but it would also make me a little nervous on the off chance you had an engine issue.
