I love this mattress. It says that it is firm but it is a comfortable firm, not hard at all. My only complaint is that I wish the edge was a little more firm when you sit down on it. If you have a low bed this will not be a concern but I have a high bed and it makes you feel like you are going to slide off.
I have owned this mattress set for one year now. BOTH sides are completely sagging, like a big valley on both sides. This is the worst possible mattress, and the Serta warranty is looking like a CRAP experience too. No refund, only a replacement IF the "independent mattress inspector" finds it to be defective. Defective means sagging 1 and 1/2 inches or greater. Cost of inspection not covered by warranty, nor is transportation for replacement. So once this mattress is determined to be defective, I cannot get refund, I MUST take a replacement mattress, and I am stuck paying the shipping. THIS IS HORRIBLE MATTRESS and THE BIGGEST RIP OFF EVER. I'm out almost $1000 for a piece of crap mattress just a year old. I bought my sons mattresses from Big Lots that are 5 years old and are in perfect condition. BLAH.
First off let me say that the mattress was shipped to our home quickly and with great "white glove service". Would recommend OS anytime! The mattress however is soft NOT firm. You sink into the mattress when you lay down in it (not on it) and if you sit on the side you feel like you are going to slide off. If you like a "soft" mattress then you would probably like this mattress. It seems well made but we prefer and though it was going to be a firm mattress so back it goes.... FYI - after the first night both of our lower backs were hurting. We actually stopped sleeping on it until the new one comes in (hopefully the "extra firm" mattress will be as advertised).