I recently slept on a memory foam mattress in a luxury hotel and loved it so I've been looking for one for a while. I chose the Serta because of the consistently high reviews -- and those reviews are totally justified.Once I got the mattress out of the box and started cutting away the layers of protective wrapping, it immediately started expanding. It reached its full size within minutes. My mattress was actually about an inch and a half wider than the box, but it's better to be too big than too small. Just be prepared for some possible sizing irregularities, which is mentioned in the item description.Since I'm sensitive to strong smells, I was concerned about a lengthy period of off-gassing. There was a slight odor (not too bad) for about 48 hours. You notice it most when you first sit or lie on the mattress since that seems to push the gas out of the foam.The Serta was initially extremely firm with almost no give, but it softened up after a day or two. I'd still rate it as pretty high on the firmness scale, so if you're looking for a squishy mattress, the Serta's not your best choice. However, it's extremely comfortable -- I overslept the first night I used it. And it was an excellent value since local mattress stores sold similar products for more than twice as much.Overall, I was very pleased with my purchase despite being sent the wrong item initially. Make sure you check the labels on the box before you open it. When I got the first box, I thought the brand on the label might have been a subsidiary of Serta but I checked and discovered it was a mistake. Overstock resolved the problem quickly and exchanged the boxes within a day.