Disadvantages
Because the design is dependent on a globe, it imposes a "covered box" situation upon any cat using it. Large cats who perch in an upright posture when using the litter box may find the interior dimensions too confining.
The manufacturer has an official size range of five to fifteen pounds. Cats or kittens less than five pounds need to have a user trigger the device manually for a cleaning cycle. Users report cats larger than fifteen pounds have used it successfully. Cats who are in the upper size range are more likely to use it if they are normal weight for their size, while overweight cats are less agile and have more difficulty.
Read more about this topic: Litter Robot