I wanted an Enclave but new priced out over what I wanted to spend ($50K+ for what I wanted) so I got my Mazda CX-9 instead. DH's car, two cars ago, was a Buick LeSabre and the car before that was an Oldsmobile he'd owned for a decade or so. The LeSabre was a former company car for one of his clients and was driven pretty much daily. Both the Buick and the Olds drove soooo well over distance, and they held up well too. I say even if it's an Old Person car, the way it drives and handles is so worth it. (And DH is not an old person nor was he old when he owned the Buick (his 30s) or the Olds (20s/30s).
I think the middle seat slides forward in the Enclave as it does in my Mazda. It's actually not too difficult for older kids to climb out of the back through the side doors, though Kiddo likes to climb out the back hatch.