Before making a purchase, I did a lot of research online, including reading reviews. The flaw that stands out to me the most is that he can be "dumb" at times. But for all of the time I used it, my vacuum cleaner never once indicated that this was the case. The one and only issue I observed was this: if you launched your robot, and it initially drove around the perimeter of the flat, you should not change the furniture until it has completed cleaning. In this scenario, when he was passing again in the place where there was nothing, suddenly some kind of hurdle appeared, and he begins to relentlessly try to conquer it, returning to this place multiple times. As a result, my recommendation is that before you begin working with your assistant, you should first set up the furniture (chairs, stools), and then allow him to clean in this configuration. The next time, rearrange this furniture in a different way, and he will go via the space where he did not go the day before.