We've owned the Litter Robot for 6 months, have 2 cats.
It is much better than having to use a regular litter box. If you are thinking about getting one I would suggest trying to find out if your cats will use a litter box that is enclosed or with a hood, as a lot of cats don't like those. There's a good website with a lot of good tips on litter boxes at:
http://www.catsinternational.org/articl ... box_1.html
In part one, about 6 paragraphs down, the article explains how a lot of cats feel about hooded or enclosed litter boxes. The whole article is actually very informative.
We are in the process of getting rid of our LR right now as we have been unable to get our cats to use it consistently, and one of them intermittently pees all over the house, usually on anything he can find that resembles a litter box. They just don't like going into the globe. We tried all the suggestions, the Feliway, Cat Attract, everything and we are tired of living with it; and I also feel this has to be stressful for our cats too, which isn't good either.
The company is very nice. They have great customer service and it is a very good product, but it didn't work for us. There are a lot of people it works for though.
We've gone back to a regular litter box for now and are looking into the ScoopFree.