I received the PetSafe - ScoopFree Self-Cleaning Litter Box, Second Generation and I absolutely love it.  I have two indoor cats and the fact I don't have to change the littee box constantly is nice.  The crystals help keep the smell down and less litter is scattered around the floor.  I love how it auto cleans when used.  When it is time to change you just pull the nox of litter out and put the lid on it.