I have a Litter Robot and like it. I use it with three of my cats (the other two live in a different part of the house as they don't all get along, and they use regular litter boxes). My 3 cats took to it right away, but they were only about six months old when I purchased it. I'm not sure if my older cats would go for it, especially my larger, 16 lb. cat. He could definitely fit in it, but it would be a very different experience for him at this point in his life. I will say that it's a tiny bit glitchy occasionally, but the glitches seem to work themselves out, and I've only had to call customer service for one issue (in the 1.5 years that I've owned it), which resulted in the company replacing the litter box liner. My extended warranty covered that expense, and I strongly encourage that you pay extra for that. I purchased it because I have neck issues, and scooping became an issue for me with so many cats. For that reason, it has been an absolute godsend. I have never had problems with mold, etc., or urine seeping down into places in the machine that it shouldn't be. When I replaced the liner, I had to take the machine apart, and everything was pretty much clean inside. Overall, I would recommend it.