We had a few LN7000 Fords with International diesels (as International Motors of Brazil, not related to International Harvestor) All except one went over 500K without total rebuilds. The one I was dissapointed with threw a rod at 380K.
I have had no experience with Ford pickups with diesels, but had 3 F250 with 351 (one Windsor, 2 Cleveland) all were good trucks. There was always too much plastic on GM picups for my taste, but they do build descent trucks. My experience is that generally that people tend to perpetuate the stories there father's had rather than real life experience. Neither Ford, not GM could have sold as many as they have if the built trucks as poorly as the stories would have you believe.
FWIW, International Motors of Brazil builds one of the best small engines today, the 2.8 TGV Powerstroke, a Variable geometry Turbo, 2.5 liter. Any engine producing over 100 lb/ft of torque per liter is a good measure in my book.