The foam rose quickly after it was unwrapped. I waited about 30 hours before sleeping on it. I've tried firm memory foam mattresses before. They were far from firm. The foam of this mattress is dense and heavy. It's FIRM. I've only slept on it a few evenings, but I've slept better those nights than I have in quite a long time. I'm hoping the firmness remains consistent and the mattress holds up. Right now, I'd highly recommend it.