My original LitterMaid lasted 9 years with little maintenance, only an occasional hosing out and some rake cleaning.  It did a decent job with the only problems coming from occasionally putting too much litter in the box.  The new model cost much more and the rake doesn't even reach the bottom of the box.  It skims the top of the litter and leaves most of the clumps, which have adhered to the box bottom and require manual scraping.