Escape rear plugs usually aren't a problem for the end user since they won't be servicing the vehicle themselves. 2.0 hours for plugs isn't that bad of a labor time, so I wouldn't consider that a downside. Plus that's only with a V6, the 4-cyl is bulletproof.
The ML is a great SUV, I own an R Class (Same basic vehicle). But, I work for Benz so It's not like I pay for anything I have to do to it.
The Hyundai's have a great warranty, so if you like those go with that. The power train warranty on a Ford is pretty fantastic, and you can get a CPO warranty for only a few grand extra at signing up to 200k miles if you want.
I wouldn't touch anything Chevy, nowadays.
The Rav 4 isn't a bad vehicle, but I think as far as comfort goes it's definitely at the back of the list.