I had a heating pad once but I couldn't assess its properties as it was very uncomfortable to use it, the stones hurt my body, no relaxation effect could happen. When I thought of buying another one, the flexibility of the mat was one of the most important criteria to consider.
This mat turned out to be the right choice for me, it's really convenient to lie on it and I can place it almost everywhere and enjoy the warmth healing my body. I use it nearly daily and notice that I feel and look better with every use. I'm going to sleep on it when winter comes.