So far so good! My cats took to this litter box quickly and had no problem using the crystals for the first time, although I kept the box unplugged for the first two days while they got used to it. Once it started doing its thing, they were a little bit afraid of it but they warmed up to it quickly because we haven't had any issues. One of my cats is intrigued by the sound, though, and he'll run to check it out every time it goes off. Because of him messing with it, it did appear to get stuck once and I couldn't turn it on by pressing the button, but this was resolved by simply unplugging and plugging it back in.