I bought the Ghostbed Flex in king size. My wife and I have been very happy with it. I was nervous at first about ordering online without trying it out first, but after reading a bunch of third party reviews and tests I decided to go with the Ghost and I am glad I did. There was no smell from the mattress when we opened it up, that was a common complaint about a lot of other brands. This made it so we could use it right away without having to let it air out. My wife wanted one made without the nasty flame retardant chemicals and the Ghost happens to work for that as well. Firmness I would say is medium... I am a back/ side sleeper and were very happy with it.