I rented this car beginning 7/17. The agency gave me a choice of this (Ford Flex) or Toyota 4runner. Given that some Toyotas (e.g. Camry and Sienna) are among the worst for head posture and other Fords and Lincolns (e.g. MKZ and Explorer) have front/aft head restraint adjustment, I picked the Flex. The vehicle had massive head restraints, which included DVD players, and pushed my head forward as most modern cars do. The first two hour drive was bearable. After that, back pain increased and resting on two points at my rear end and head wouldn't work for more than a minute or two at a time. I eventually partially inflated a couple of airplane neck rest pillows and placed them behind my back for more continuous support. That was more bearable, albeit slightly unstable. However, traveling by air limited the ability to bring a larger cushion to push my body an inch or two forward. The head restraint, like many modern restraints, was designed to assume that I either slouched back while driving or had another inch or two of body fat between my spine and the back of the seat.