I heard and researched a ton of info before deciding to attempt purchasing a 6.0 so I knew what I was getting myself into. Found a 2005 Ex with 135k on it and had an oasis report done and borrowed a monitor to verify engine health. All checked out good but even still at about 138k I lost the HPOP, two injectors and the IPR valve.
id say your issue was poor maintenance by the previous owner. the manual that comes with the powerstroke equipped vehicles even says that poor maintenance is detrimental to the health of the high pressure oil system and injectors. (not preaching, just an observation)
now, the 6.0 debate. i love my 04 CC FX4. shes deleted and oil cooler relocated. studs? no clue. previous owner put quite a bit of money into it (BPD EGR delete (-gutted cooler-) and Oil Cooler Relocation kit, RC 4" lift) and im driving it daily, and towing a 8.5X16ft tandem enclosed trailer often. im running an SCT livewire and a canned tow tune, and she runs like a champ. it really is a hit or a miss, and can vary greatly depending on how the previous owner(s) treated the truck. im not gonna lie, i dont baby it anymore, but i dont beat on it. ive decided if its going to go pop, its gonna happen no matter what. im running Rotella T6 and a bottle of Diesel Kleen every fill-up (cost me $5 at work
that being said, before my grandfather passed away, he ordered a F350 CC Lariat dually with the 6.0 and 5spd auto when it was the split year (7.3 or 6.0) in 2003. my uncle talked him into the 6.0, since it was the new and improved Powerstroke. the truck was regularly used to tow a 30ft gooseneck loaded with tractors and other equipment, horse trailers, cattle trailers, etc.. the truck amazed me with the power it had, and it felt like the load wasnt even behind it. it was a work truck. it was regularly maintained by the dealership, and still is today even after my grandfather passed away. both my uncles still use it for hauling. that truck is an 03, and the only two issues its ever had have been a door switch going bad, which ran the batteries down, and the Unison ring in the turbo froze, and Yadkin Valley Ford (local dealership) replaced the turbo under warranty.
thats been it. the truck has never been deleted or modified.