My 03 6.0L is going strong with 218,000km's on it. Original headgaskets, head bolts, oil and EGR coolers (the 03's rarely IF ever blow an EGR cooler). The truck has followed the ford maintenance plan since it was bought new. I'm the second owner of it and it was purchased from the dealership I pull wrenches at. The previous owner pulled a 36 foot 5th wheel with it all summer since he bought it.
If you maintain them, change the oil every 5000km's, change the fuel filters every 10,000kms, and flush your coolant regularly (or switch to an EC-1 ranted ELC coolant) You will have many many trouble free miles out of your 6.0L. They run like a raped ape, and put the 7.3L to shame.
I love the Ex's! and that color really does look good on it! You've got my vote!