The Roomba for what it is, is great. I previously had the Roomba 880, and the S9 is significantly better. It doesn't miss the spots the 880 did, and with several dogs, the auto bin emptying assures the Roomba will vacuum on schedule without worrying about a full bin. The biggest and only issue I have had is error 21. The Roomba will start and about twenty minutes in, shuts off and says it is having a navigation issue. Roomba has agreed to replace the Roomba, however I have not received it yet. If it didn't have this issue, it would hands down be 5 stars.