I have an '06 with the 6.0. I take very good care of it, all the oil changes etc on time every time. I had the bulletproofing done at 140,000 miles and essentially rebuilt the entire top end. I find this truck to be extremely reliable IF the EPA crap is pulled off. The problem was not with the engine. It is very strong and reliable. It is the emissions stuff added on that has caused the problems. I decided to spend the money on this one instead of buying new because I love this truck!
There is only one (easy) way to see if a 6.0 has been bulletproofed and that is to look at the head studs. Lots of pics online showing what that looks like (https://www.ford-trucks.com/forums/930633-how-can-you-tell-if-the-head-bolts-have-been-replaced.html). If the head studs have been replaced it makes sense the whole bulletproofing was done. The only other way is to check for an EGR delete, not as easy but a mechanic should be able to figure that out in an hour or so depending on the method used.
The emissions stuff has been deleted, and still passes smog test with no issue. I then put a programmer on it and it runs like a scalded cat when I want it to, and all the power I could ask for when I put on that program. Mileage went up, engine runs cooler and just as clean. Plenty of power to tow whatever I want.