What would reviews about the best pillow top mattresses say? I believe these are the kinds of mattresses that have pillows actually built into the mattress. By definition, a pillow top mattress is a mattress that has extra foam padding built into the mattress and it looks like a pillow has been built into the mattress. Naturally, these types of mattresses may cost more than regular mattresses because of the extra foam on the surface of the mattress. The extra foam can be made of several types of material. I do not mean the actual layer itself is made of different kinds of material. I mean that the whole extra layer of foam can be made out of several individual types of materials. The padding will be made of all the same type of material. It is also supposed to supply the person sleeping on it extra softness.