I too had a 6.0L that I wouldn't classify as one of the nightmare trucks but it was starting to have issues that I knew were going to be expensive so I chose to upgrade. I got hosed on resale value on the 6.0L as most people do because they are not a desirable truck.
In regards to the Ford 6.7L, they are hands down much better than the 6.0L was. They had a fair few problems when they came out but the main one that scared me away was the high pressure fuel pump failures that trashes the entire fuel system to the tune of around $12k plus that Ford tends not to warranty. There is a forum member here named Ricatic that had a 2011 Ford 6.7L that this happened to that Ford would not warranty; I am very thankful that he was very open about his nightmare (which Ford did not cover under warranty) because it helped me make a much more informed decision.
I would also encourage you to look at the complexity of the Ford 6.7L under the hood compared to the Ram Cummins 6.7L; you will quickly see how much more complex the Ford is which will certainly lead to higher repair costs in the future.
I knew that I was going to keep my truck for a very long time so repair costs was a major consideration for me. I had the issues with the 6.0L and just simply decided that I needed to open my eyes on an upgrade. I made a change after 20 years of owning Fords and I have no regrets. I would strongly recommend you have a look at all of the brands prior to simply jumping into another Ford. JMHO.
