I have a 2005 F-350 6.0 and have had no problems but there are things that you need to know before getting one.
1. Get an oasis report from the dealer before you buy,just take the Vin. number in and have it run. It will give you an idea of what has been done to it at the dealer.
2. If you get it, get a ScanGauge. These can be set up to monitor the difference in water temp and oil temp. and is an early indicator when something is starting to fail. It also will measure the voltage to the Fuel injection control module (FICM) lower tham 48v means it needs to be replaced or injectors may start to fail.
3. You must drive it at least once a month to keep the turbo from binding up due to none use(rust?).
4. Change fluids religiously especially the coolant,and add a coolant filter.
There are more things but I just can't think of them now. You may want to go to Dieselstop.com for added research.