Is there a year F250/350 6.7 to avoid?

I have decided that I want to get a little more truck for pulling the 5er. We are going to need to replace my DW Navigator so I think we will keep mine and replace hers with a newer diesel. I have never and will never by a "new" truck so I will have a broad range of years I can look for. I have been out of the dealer for s few years so I have not seen the issues I used to before hand so I am asking the experts on here. Is there any year or years that need to be avoided for mechanical/ design issues or power/ mpg issues? Any help will be appreciated.


2000 F250 CC 4x4 7.3L diesel

15 Salem Hemisphere Lite356QB