I've never owned a 6.0 or 6.4....just the venerable 7.3. And every one of my trucks have had well over 200k miles with very little problems or upkeep. I love the engine. The next one I buy will depend on when I buy it. If its in a year or 2 it will be the 05 6.0. I never buy a truck with a newly designed engine. I wouldnt even have a 08 6.4 right now. Would wait for a couple of model years until they get all the bugs worked out. Just like the 6.0, I wouldnt buy an 03-04, when they were brand new, just because they hadnt got the bugs worked out from the factory until about 05