Wife and I are both 5'9" and we loath the seats. Incredibly uncomfortable if you're trying to sleep - we both walk off the JFK-HKG HKG-JFK flights with back pain and usually need to go to see a doctor to get adjusted after the flight. Never had the same problem with the old seats on long haul flights.

I hope they reconsider the design. There's something wrong with the ergonomics of the seat design and where weight from your body gets distributed.

I'd imagine if you're staying up the entire flight there's less of an issue as you wouldn;t recline if you're watch movies or working on a laptop.