My experience with the Litter Robot has been very good. With three indoor-only cats, it has lasted just fine. My mom’s considering purchasing her third Robot—the first two are working fine after a year and a half, but with 10 cats it pays to be safe!
Incidentally, I did have one problem with it that was at least partially operator error—the plastic trash bag I had put in the waste drawer got caught in the wheel that turns the drum—but it was still under warranty, and the company cheerfully took it back and fixed it. I have nothing but praise for the company and the product.