As all the other reviews stated they they were apprehensive about buying a bed in a box. But after muscling the box upstairs and cutting ( with the enclosed cutter) the mattress out of the plastic, it did its thing! The mattress expanded to 10 inches within minutes with no foul smell.  We slept on it that night, feel can be personal but our medium was more firm. The overall sleep was good and the preceding night was even better. All I need to see now is the long term durability.