The ones I’ve seen are not cheap and I don’t know which ones work well.
Thanks in advance.
Hi! 
I had a Littermaid Mega for the longest time. I didn’t like the plastic blades. The new ones on the “Elite” are metal which I think is a great improvement.
http://www.petsmart.com/product/index.jsp?productId=2750953&cp=2767033.2769041&view=all&fbx=0&fbn=Taxonomy%7CLitter+Boxes&f=Taxonomy%2FPET%2F2769041&fbc=1&parentPage=family&keepsr=1
Plus: Automatic, Worked great for 3 cats
Negagitives: Trays the clums go into are about $14 for 12. That to me was a bit expensive for something that merely houses poop. Occasionally, one cat would go right after the other. In that instance sometimes the clumps would be too heavy and I would have to manually scoop.
No lid-I have one cat who covers rather vigerously and many times he sprayed litter over the sides of the box.
I have said if I ever can afford another automatic litter box (the original died after about 3 years of use) I was going to get this one:
http://www.petco.com/product/100015/Petmate-Purrforma-XL-Self-Cleaning-Litter-Box.aspx
It has features I didn’t like about the Littermaid such as a hood. It also used bags for disposal rather than the big plastic trays. I have seen the bags for sale for $2.99 a pack.
I have 3 cats, but one was a 'fraidy cat and wouldn’t use it. We finally gave up on it and went back to the old pans. We also have a pan for each of our cats. They seem to prefer that and at a 100 bucks per (that’s what I paid for the first auto-scooper), felt that 3 were out of the question.
Cheesiesmom
This is something that I need to look in to. I have 2 cats and it seems that one of us is always cleaning that box. It’s plastic which is definitely a pain. I never thought to use an automatic litter cleaner before, but I may have to rethink that. I don’t think my husband will have a problem with an auto litter cleaner.
Thanks for the info.
One thing to mention. There is a round self scooping litter box too. I returned it. Horrible thing. My Sydney couldn’t even fit in it. He’s 18 lbs.
Also when you look at them, don’t be afraid to open them in the store. You have a right to know what you are purchasing. Make sure the rake comes off easily. I know the Littermaid did, but since they changed models I would double check. You definitely want to be able to take the rake off-it makes cleaning SO much easier!
Unfortunately, they don’t make an automatic litter box that can meet the needs of 9 cats! But, we did have a littermaid years ago when we only had 2 cats, and it did a good enough job. I imagine with the improvement to the blades it works even better.
I can tell you we had a terrible experience with a “flushing” litter box that connects to a water source and a drain. The mechanics worked fine, but the odor when the water would “wash” the “litter” was just unbearable. Also, it was noisy, and though the cats used it, I don’t think they were crazy about it. They are super expensive, so it was sent back. That’s been a few years ago and there may have been improvements, but those are the negatives I can remember.
I’ve thought about purchasing an automatic can pan, but was hesitant because I didn’t actually “know” anyone that had ever used one. I have 4 indoor cats and it seems we are continually cleaning out their pans.
I have a 20 pound cat that I wasn’t sure would even fit into one. They seem to do pretty well with the old style, but automatic seems pretty happening! LOL!
NC girl - I had a kitty that was 20+ pounds at the time we had the littermaid (it was the largest one they made) and he did fine. I don’t know if it would do well for 4 cats, though. Maybe someone else has used it with that many and can tell you for sure.
I was given one from my aunt when he cat passed and it was AMAZING. We bought one stack of the plastic trays for 15 bucks and never bought more. They are plastic and we found they never got very gross, the litter did a decent job keeping things from being too sticky… so we would just soak them in hot water in the sink in the basement and give them a quick scrub. Saved us a ton of cash
I don’t remember what machine we had, but it was very loud (I could hear it in my room on the 2nd floor and it was in the basment. and it did eventually break.