Ok start out with...It took a full 48 hours before it reaches its 14" ….even on the ends on each corner is still only 13".   I waited 48 hours before sleeping the mattress.  Very comfortable.  Not for sure how it would be for someone with back problems, its more plush to me than medium.   I love it.   Giving it the full 100 days to make sure it holds up.   Otherwise Im very happy.