I bought this for my elderly cat on the recommendation of my vet (it came as part of the Thermo-Kitty Bed). Granted, it has been used almost daily for over a year, but today, it died. I am more than a little annoyed, since I don't relish spending another $30 for the replacement heater when the whole bed only cost $42!
My cat does enjoy it, and since I keep the temperature of my house around 58F when I am not home, I will buy a new one for her. I just wish it hadn't broken just outside of the warranty window.