I bought one of those covered cat little boxes with the filter on top and the swinging door to try out - and lo and behold, my two use it! I didn't think they would because they are the types who like to stand with their front paws on the edge of the little box when doing their business, plus I figured the swinging door would freak them out. But they really seem to like how much bigger the pan is and I like that I can have one in the kitchen and not gross out my guests :-) They also do help with the poop smell - I don't know how much good the filter is, but the hood on the box keeps smells inside. Emily [Posted in FML issue 4519]