mrburnette:
My daughter has a commercial unit purchased at a yard sale. It works well, requires a premium grade "clumping" litter, special plastic bags, etc. But, it works and the cat seems not to mind the experience... She will sometimes watch as the machine rakes her business into the collection bin... But she has never attacked it. She will become very angry if the machine is stuck of fails to cycle upon her next visit, however!
If I program a delay in the cleaning cycle that should help keep it together.