You are looking to upgrade your innerspring mattress now that it is not as firm as it used to be. After researching and learning about the different types of mattresses that are in the market today, you have decided to buy the best memory foam mattress. This is a mattress that is made from memory foam, which is a visco-elastic material that is both pressure and temperature sensitive. A memory foam mattress conforms to the shape of your body when you lie on it making it very comfortable. There are a number of things to consider when buying a memory form mattress.