Pillow top mattresses king size describe an added feature to the construction of the mattress. You can get a mattress with or without a mattress. If you want softness and good support, choose a firmer mattress with a padded top added. You can buy a mattress with an attached mattress or you can get a separate pad that attaches to your existing mattress.
Pillow tops come in a variety of materials, with cheap ones mainly composed of memory foam or latex. These sheets to help relieve the pressure of sensitive joints and pressure points by adding a layer of softness, can help regulate body temperature and tend to stimulate less allergies, but can be difficult to clean. Feathers and down leaves to clean easier, but can attach over time and cause allergies. Wool quilts help retain body heat, but tend to flatten over time as well.
The best way to choose a mattress and topper is to visit a mattress store and lay on the bed for a few minutes. Heavier people and the sleeping stomach and back may prefer a firmer mattress, while sleeping on their side and people with arthritis or other joint disorders may prefer a softer mattress. Your doctor may be able to offer advice if you suffer from bones or joints. In addition, it is often easier to add a layer of softness to a mattress that is too firm to add support for a mattress that is too soft.