I have had my cat genie for over 2 years and I love it! I highly recommend the scent free cartridges. The scented ones are just very strong for me. These things last forever and definitely make it worth the price. I have it set to cat mode and I only have one cat so these things last several months. Totally worth it when you look at the cost you would spend to have to keep buying litter each month! And there is no nasty smell!