I think overall they are a good truck. I may get flamed for this, but you may want to do a search on the high pressure fuel pump issues on the Ford 6.7L engine. These pumps are known to self destruct and fill the entire fuel system full of metal shavings which destroys essentially everything in the fuel system requiring it to be replaced. I have heard this can cost $12k or more to repair. Ford has been known to deny warranty claims for this issue claiming water was present in the fuel even though owners have drained the fuel/water separator and the water in fuel light did not illuminate. The GM Duramax uses this pump as well and has also experienced these failures but it is my understanding that they warranty the issue.
This problem appears to be relatively rare, although exact numbers seem to be a mystery. It is not an issue until it happens to you I guess, although I have read at least 2 claims of this issue on this forum alone.
I ultimately decided not to purchase the Ford 6.7L diesel and this issue played a large part of that decision. I plan on keeping my truck a long time and simply did not want to chance this happening, especially when the truck is off warranty. This may or may not play a part in your decision but you should at least be aware of the potential for this issue.
Good luck and let us know how things work out!