The Pentastar V6 is a good engine and they're everywhere. It's normally aspirated too. If you're going to get rid of it after a few years, I might lean I4 if premium didn't cost more than diesel in my area (I think that's currently a bit of an exaggeration).
I typically don't like V6s, but for a gas engine adding a turbo, you kinda complicate things a bit for off-road use IMO. But really that stuff doesn't mean that much anymore since they're all designed to last for a similar amount of miles and then stuck in the junkyard. Typically you're going to have a bunch of flat tires, accessories, suspension, etc stuff that's going to fail long before the engine if you're half way easy on it and do the prescribed maintenance. I would figure 200k miles staying mostly on top of the vehicle would be typical for either engine and from there the V6 will likely be cheaper to replace, but there may be an easier option to rebuild the 4 cylinder.
That I4 may be even fancier though. It's not a hybrid or anything is it?