My Husband bought this for me recently. I set it up, my cat used it the first day and has been using it every day since!
I allowed my cat to be around when I started the unit yesterday - I've closed the door previously so he could get used to the sound but not get scared - and he checked it out and sat next to me the entire time the Cat Genie ran. He wasn't 100% sure about it while it was running, but he used it without hesitation last night and this morning.
I love that I haven't touched cat litter in a week!