I like the box and it does eliminate the mess and hassle of freshening up the litter box.  The only negative I have is that it feels a little pricey to buy replacement trays.  I'd be interested to learn about the permanent tray that I've seen mentioned in other reviews so I could just buy the crystals.  However, that would probably negate much of the convenience.   It really does handle odors better that regular bulk litter that we were using before!