I have given the PetSafe-ScoopFree Classic Self-Cleaning Litter Box a total of 10 days trial and my 7 year old female kitty will absolutely NOT go near it.  I have tried all of the tips and tricks suggested, such as letting her other litter box go without cleaning so she'd feel compelled to use the nice, clean litter, but - that did NOT work.  I carefully have watched her approach the litter box and each and every time she steps onto the litter she freaks out - I'm assuming it is because of the texture of the crystals.  I'm sure she knows what to do - it's just that she simply will NOT be doing it in this box.  I'm sorry - it seemed like a really good idea.