Based on our own experience, memory foam mattresses work well with both types of sleepers. The reason behind this is its density and conforming properties that allow it to provide cushioning and support for side and back sleepers. For example, a side sleeper can stay in neutral position for an extended period of time because the memory foam allows the shoulders and hips to sink while supporting the rest of the body. When it comes to back sleepers, memory foam allows their bottoms to sink in while contouring the curves of the lower back for support. However, if you are a stomach sleeper, you might want to think twice before getting a memory foam mattress. While it allows the waist and pelvic area to sink in, it puts the spine in a curved position and pushes more pressure on the lower back area.