Shortly after we purchased this mattress, I noticed that there is a ridge going down the middle of the bed, which makes you gravitate to one side or the other. It takes some effort to roll over this hump. After four years, we virtually have two hammocks with the center ridge even more prominent. We waited a long time to get a mattress and I could not be more dissatisfied with this product. What gets me out of bed each morning? Back pain.