If both cliff sensors (I ordered 2) worked I would give this one a 5; But having a movement myself was great for the price (which I would expect from a product that is over 10 years old). I would be just as happy to pay the same amount for a working cliff sensor. I believe the cost was under $25 and I was able to get my Roomba running like new again! I can only hope it continues to work as replacing the breakage sensors is a lot more of a hassle than having one of them not working. Overall I'm still very happy with the purchase and would recommend it to anyone if their robot vacuum starts its circle dance and dies.