I'm not going to make this a brand thing because I am a Cummins guy. I am the shop manager at a fairly big construction company and I take care of 5 6.0's and they are great motors when taken care of. They are a little lacking in power for towing at interstate speeds but I can tell you that you are not going to hurt them buy running the dog doo out of them. As a matter of a fact the EGR problems (stopping up of the intake and EGR valve are caused by babying the truck. Believe me when I say "put your foot in it" the 6.0 loves to run hard.
My service truck is a '06 F350 CC with 4:11 gears and has 140,000 miles on it and I have been through it all with 4 of the trucks. EGR deletes because of idling all day on jobsites in the winter months. The EGR cool problem is a problem caused by silica that was used to clean the blocks out when being built and not all of it got removed. The coolers on these motors have very small passages that the coolant flows through that get stopped up with this silica. This in-turn causes an unexpected overheat condition 90% of the time when under a load only that will very easily warp the heads causing it to burn the coolant. I went through this with 2 of the trucks. Easy fix is an inexpensive aftermarket coolant filter for around $130.
6.0L Powerstoke Bullet Proof part 1 - Coolant change and filter install
The next thing on a 6.0 is injectors. Fuel pressure is the main killer of the injectors on the 6.0. The injectors are capable of "pulling the fuel if the supply isn't there which will "pull" the o-rings right off of the injector. Also the fuel also acts as a coolant for the injectors and when it don't get enough coolant....well we all know what happens. The first mod to do is to get a good set of gauges and put them on the truck. Fuel pressure and EGT would be the first.
The next thing is replace the fuel pressure regulator spring. Ford has an upgrade kit (Ford Part number #3C3Z-9T517-AG) for around $80-$100. You can also get it through an International big truck parts house. International part number #1854267c94 for the spring and gaskets. 40.00 at most international dealerships. For the equiv. International part just the spring and the seal is part number #6E7Z-9C165-B.
They also had a hard hot start problem that was o-rings in the high pressure oil passages in the heads. I think Ford charges $1400 to fix this problem but with about 20-30 dollars worth of parts and about 4 hours and anybody with a little wrench turning since can do it. It looks worse than it really is. I have had 3 of our trucks down to the block. They are not as bad to work on as many people put out.