Really? I have a little experience with a 6.0 PS, which everyone was hating on back then, but nothing newer. I remember people always hating on the 6.0 saying how weak and bad it was, but the F550 I drove around never had any real issues, it was just a picky bitch with the fuel system. I though the next engine was suppose to have fix all of the perceived short comings of the 6.0. My neighbor's truck is whatever replace the 6.0 PS, and I can tell you one thing, it's always broken. I remember last year he spent something like $8K on fixing it, got the truck back and the next day he broke down in the middle of a very busy 4-way intersection. I was home when the roll back dropped it off, again.
While I type this his truck has been MIA for the last 2-3 months. I assumed he wised up and sold or scraped it, but when I asked his kid about it last week, she said it's in the shop.