I'm giving this 1 star only because there is no option for fewer. Maybe this litter box works for cats who always go in the center of the box, but for those that go more towards the side, this is a real waste of money and I have spent more time cleaning it than I would have to spend on a regular litter box. Also, if your cat has large pees, the chances are that the waste receptacle won't close as the clump will get stuck and the lid won't come down - not pleasant for us or the cats. The rake and the sides are extremely difficult to clean properly. Besides which - this is so noisy that, if you have the litter box anywhere near a sleeping area, you'll want to switch it off at night.