Littermaids are great for single cats or smaller kitties... mine are all bigger than my Yorkies, lol.... with multiples they all tend to want to use the box at the same time, like one after the other, back to back, and even the mega littermaid can't handle it. I went back to using a regular box and I put a Litter Locker right next to it, and I just pick up after the cats more often, which is a lot easier than dismantleing the Litter Maid and cleaning it every other day when it clogs. Also found out that the Diaper Genie (for human babies) refills are half the price of the Litter Locker bag refills and fit into the Litter Locker just fine.
My one kitty would sit outside the box and trigger the sensor with his paw just to watch the rake move!
Expensive cat toy!