Serta sheep dreams mattress may be the best mattress I have ever owned. Unfortunately for me it went on my sons bed. The mattress was delivered quickly. Easy open out of the box, cut the plastic, put it on the bed and time for expansion. Expanded quicker than I expected. The mattress is 12 inches thick, fit my standard box perfectly. I would call it more of a medium-not firm but not too soft. Has great support, but not at all hard. Sleeps very comfortably, and doesn’t seem too hot, which can be an issue with some memory foam mattresses. I’m so pleased with this mattress I am going to purchase another for my master bedroom.