I would have given this mattress a 5-star rating because it cured my hip and back pain after the first night I used it. That being said, the chemical smell has been terrible--definitely has lasted for several weeks, despite airing it out by propping it up near an open window, using two mattress pads and changing the sheets every few days. The other complaint I have is that both my husband and I have noticed that it retains a fair amount of heat during the night.