We have four cats and I'm seriously considering a litter robot. 3 of the cats should be fine with it, the 4th might have problems both with weight and stool issues.
I don't think out two girls would have a problem--the older one is petite. The younger one is still growing, but she is over the five pound minimum. I'm also pretty confident that our oldest male would fit if he decided to use it--he's 14 pounds, but he's long and well proportioned for his weight, with just a little excess weight around the tummy since he became a senior.
Our other male cat though, is, well, round. He actually has a small frame, which makes his 16 pounds look even more ridiculous, but so far we haven't gotten anywhere with having him lose weight. He isn't much over the recommended weight, but I'm seriously wondering how well he'd fit through the door. I know some people with larger cats use the litter robot, but are those cats big, long cats or beach balls like my baby? Any thoughts? My other question may be a little gross, but this is a litter box forum. This same cat has megacolon. Because of this and the medicine he takes, he can vary between large hard stools (the megacolon) and diarrhea (the side effects of the medicine). Obviously we try to keep him somewhere in between, but it's a difficult balancing act. Does anyone have any experience with how well the Litter Robot copes with "loose stools"? I don't want to end up with difficult to clean smears all over the interior of the globe.

