We have from two to four cats at a time in our home, and managing the litter box is something we want to be as easy as possible. This LitterMaid LM500 Automated Litter Box was the first automated solution we tried. I'm afraid it wasn't our last, as it had numerous problems.
First, the tines would get clumped full of stuff and it would get caked solid rather quickly. I'll note that we didn't even try having this be the "only" litter box in our home! We had two others there too. We just wanted to see how well this worked. The storage container would get jammed in the open position, so that it did not do a good job of managing stench.
However, we could have dealt with those issues. We could have cleaned the tines daily, and pushed down the lid ourselves regularly. The real problem was far more serious.
First, understand how this works. The system sense motion and then X minutes after the cat has left the area, the tines move across, dragging any solids and clumps with it, pushing those items into the receptacle plastic box at the far end. Then the tines return to their original position and wait for a new visit.
What happened with our unit would be that the tines would decide that they were ALWAYS ON and would keep going back and forth, back and forth, driving the poor kitties to distraction. There was no way they were going to jump in there and try to do their business while a set of metal tines was growling towards them!
We tried several times to fix this, but it really just wasn't worth it. We moved on to other options and found a GREAT one. This one went in the trash as we couldn't even imagine subjecting any other cat owner to it. A large waste of money.
Not well recommended.
I'll give it 2/5 stars on the assumption that some units do NOT do that random motion thing - but it would only take one fritz in a lifetime to really demolish a cat's desire to ever use the unit again