I have two Cat Genie 120's for my 5 cats. They took to ithe first one right away. That is why I ordered a 2nd one 2 months later. The cats were used to the crystal litter and covered automatic litter pans, so the noise did not upset them.
I have found that since the granules do "track", I keep a black rug in front of the boxes and then I can shake the granules back into the boxes once a day. The box is situated where only the cats walk on the rug, so there is nothing else on the rug when I shake it back into the Cat Genie.
The Cat Genie is absolutely the most exciting thing I have seen in my many years of owning cats.