If you want reliability, the Ford v6 turbo aint it. When you put in a water pump inside the motor needing an engine out service to replace it, that's a problem for the used consumer. If you want all out reliability, with zero BS, get a GM with a non AFM 6.0. Designed in the stone ages, serviceable by any capable toddler, guaranteed to hit 300k with no issue if you maintain it. However, it is a less 'cool' truck. I've been looking for quite some time about the 'right' 2500 for me, and I was laser focused on GM and the 6.0. I opened my eyes up a bit, got the extended warranty on top of the CPO warranty for my RAM, and the rest is history. I like the truck a lot. LIKE A LOT. Huge aftermarket to make it your own. However, if you're looking for a suggestion between the 5.7 or the 6.4, I think they're nearly the same motor. Same quirks, same shortcomings, and same level of reliability from what I can tell. I'm pretty new to the RAM game, but I keep my eyes open and my ears on to get a pulse on the owner. Again, I like it so far, and I'm pretty confident it'll go 200k with little issue.