Let's not make this a 6.0 bash. Majority of the negative opinions about it are coming from people that were clueless and really don't know a damn thing about them. Maintenance is key, run 5w40 synthetic and change it every 5,000 miles along with the updated items and you'll have a reliable truck. I'm about to roll 170,000mi on stock heads and bolts and I tow heavy with a MILD tune.
You want to talk costly wait until warranty is up on those 6.7s and the fuel pump pollutes the fuel system. Hope you have 12 grand set aside. And the 6.4's are usually wore out so bad @ 100,000mi. that when they grenade they are not even servicable.
Buy a 6.0, put maybe 1000 or worse case scenario 5 into it and you have a truck that can go 500,000mi.
Point is they all have issues includes the almighty Cummins with blown head gaskets. You can only squeeze so much juice from an orange and with emission standards and the HP & TQ war among the top 3 these trucks are running on edge. It's all how far you push them. Here's a little educational video if your in the market.