I have gone through 2 of these in 5 years.  NEVER again will I purchase a a Littermaid.  This model died Monday after 2-1/2 years, but had been having problems with the rake running continuously until it finally cut off.  The cord finally snapped on Monday.  Not only the short lifespan considering the price, but I found myself spending nearly as much time cleaning the box as I did a regular old litter pan.  No matter what litter brand I tried, it adhered like mud to the bottom of the pan, would stick to the rake, and eventually cause the machine to cut off.