I have had two of these.  The first one froze with the rake in the air about 3 months after I bought it and I could never get it to retract. The second one has been in use for over 18 months now and is great for keeping most of the material racked up.  But as many people have stated, material does cake up on the rake and sometimes on the base or in a corner depending on how often and where your cats pee mostly.  So I do periodically have to take a traditional litter rake to the base to losen material so the rake will catch it and rake it into the tub. 

You do have to keep an eye on it if you...