I don't think I could live without the CatGenie anymore. It's the best litter box there is! I have 3 cats and was having to change a lot of litter boxes. Not only was it messy, but litter was expensive. We purchased 2 CatGenie 120s and set them up in July of 2010. The 2 CatGenie 120s have have made it a lot better for all of us.
The cats are a lot cleaner too, something I didn't expect as a bonus. Apparently, the litter made their fur dirty, and I didn't even realize it. Their coats are much softer now. So we're all cleaner.
You do have to run the maintenance pack and they include one with each CatGenie 120 you purchase as well as an extra box of granules (2 total) and one cartridge. Though the initial purchase price is about 8X more than a good litter box, it costs at least a little less per month for supplies, and it's so much easier than changing litter boxes besides being more sanitary.
As I said, we have 2 CatGenie 120s, We also did have some minor issues which required their customer service, but they were great about it, solved the problems in a very satisfactory manner. CatGenie could also come up with a mat for the unit to cut down on litter in wet places.
I also recommend the CatGenie GenieDome. The GenieDome includes the CatGenie SideWalls for CatGenie 120. Even my largest, 15 lb. cat, uses the full dome comfortably, and it also helps keep down the spread of granules.
We also had an "accident" before setting up the second CatGenie 120 so that I definitely recommend 2 of them for 3+ cats, especially in the recommended--and better--automatic-activation mode. One of my cats has also twice mistaken an open box with newspapers and magazines for a litter box so that I have had to try to eliminate open boxes which could confuse him. I believe the manufacturer also recommends 2 cats per CatGenie 120, possibly 3, but we definitely needed the second unit for my 3 cats.
One of our CatGenies is in the bathroom, and the other's in the utility room. Moreover, we now have the one in the bathroom directly plugged into the plumbing rather than draining into the toilet, and I recommend doing it this way if you can because it makes it eliminates the ring draining into the toilet can cause.
Anyway, to paraphrase another review I saw, the CatGenie 120's not perfect, but it's great! The benefits outweigh the costs. It really cuts down your work on changing litter, somewhat on its monthly expense, and it makes it a lot cleaner--more sanitary--the cats and everything else! It's the best automatic litter box on the market.