When you set out on an expedition to buy a mattress, be sure that you've got your research in hand so you'll understand all the available options. If you've already looked through several mattress review sites, then you'll know that you've got the choice of springs, alternating pressure (a sophisticated, electronically-controlled air mattress), or foam, specifically visco memory foam. You'll also know the different types in each category, and the pros and cons of all of them.

Any mattress review will demonstrate that spring mattresses are a long-time standard by which everything else is measured. Even memory foam and the high-tech air mattresses are compared to springs. And in fact, there are those who want the extra give of springs but also want the support of foam, so they often will buy a memory foam topper to put on top of their spring mattress. This gives them that extra bounce but also provides some of the support and softness experienced with visco elastic foam.

Springs can lose their shape eventually, but foam mattresses may also do so. Various types of reviews on mattresses will point out the difference between ordinary foam and memory foam. The latter is much denser, with millions of tiny cells that soften with body heat but "remember" their original shape as they cool. So a mattress made of ordinary foam will flatten much sooner than one made from memory foam.

Another comparison you might find would be between memory foam and the alternating pressure mattress. This mattress has small air cells inside that are inflated and deflated with electric controls. Studies have shown that both the visco memory foam mattress and this air mattress give better support than other types. Yet it was the alternating air pressure mattress that did the best job of preventing bedsores, because the force pressing on a person's body differed from time to time.

With so many different types of mattress out there, and so many options within each category, mattress review sites will provide invaluable information for you, and can provide a lot of tips. You might decide that a good spring mattress is exactly what you want, or perhaps you'll look into an air mattress. Whether you choose one of those, or go for a 2, 3 or 4 inch memory foam mattress, these reviews will definitely give you plenty of information.