This rating has been updated based on additional product experience and correspondence with the manufacturer, as detailed below. This is from the same manufacturer as the Proscenic robot vacuums and we bought it as a replacement with the manufacturer's approval. after problems with two proscenics. The first Proscenic broke down in less than two years and the second (different model) had two problems in less than six months. We returned this Ultenic less than a week later because it had navigation issues similar to those we had with our second Proscenic. . It stalled due to numerous side brush and sensor failures, and as shown in the attached video, shortly after leaving base with a full charge for a scheduled auto-clean, it frequently reversed direction, returned to base, and then moved back without cleaning until finally the direction was manually corrected or restarted. Overall the machine was pretty good: low profile under furniture, good speed (although not as fast as the seller's video), strong suction, easy emptying, good build feel. Bad: Random cleaning pattern (not back and forth like seller's video), firmware didn't feel fully polished, Android app didn't show a cleaned area (like seller's photo). Three stars because we are very happy with all three Proscenic/Ultenic products when they have worked properly. But ONLY three stars due to repeated issues with the manufacturer's products and a frustrating, nearly month-long email complaints process for a previous product that ended up giving us a two-star review on this device, to our satisfaction, within 12 hours of first posting it has been resolved. Be honest, we can't update this review if the product improves after we brought it back. We invite readers to consider what we have published in light of subsequent reviews. However, based on our conversations with customer service, we advise readers to be wary of glowing five-star reviews.