No experience with them, but IMO, I think it's nothing more than a gimmick. With proper care and maintenance of your tank(s), I think UV is a waste of time. I had an external UV(Turbo Twist) on one of my tanks and thought "wow look how clear the water is". Then after the bulb burned out, I realized that my water was just as clear and my fish just as healthy as before. I could watch undistorted TV through the tank if I wanted. So no more UV for me!