we have had shit luck with the 6.7 fords at work both engine and transmission problem in the last 3 years.
Some of the earlier 11 and 12 Fords did have some issues, most were turbo and valve issues. I have a buddy that just blew up his 6.7 Ford just a few weeks back (2011). About $18,000 for a new motor. Yes, 18 frickin k !! OUCH.. that being said, I'll give them the benefit of the doubt since they are again, a new motor design (at least for the 11's and 12's). You will find it hard to find guys with 13-15's that have had motor or transmission issues... those issues seemed to have been resolved... and the 6.7 now looks like its turning into the reliable monster that the old 7.3 used to be... on facebook there is a "North Dakota Diesel Crew"... the shear amount of guys that have switched from Duramax to Powerstroke is astonishing. No doubt that most of those guys' parents probably paid for the pickup, and havent seen a second of gravel road time... but if you ask them... they have had stellar luck with the new 6.7's.