I bought a new 2015 F350 6.7 last year. I have about 11,000 miles on it. It has run like a top so far. I have no mechanical abilities so I cannot offer any techno-talk, but I can say I've had zero issues with it. I tow a horse trailer throughout Washington and sometimes down into Oregon. It's like the horses and trailer aren't even back there.
No gripes here on the 6.7.
