This was my third Roomba - I keep hoping iRobot will make one that really works. They get better and this one cleans well, but the software makes it very difficult to get the house mapped. There are no published "rules" and each call to support yields a variant of how it works and the suggestion to "try again". The support people are wonderful but I have the sense that they do not have enough information about how things actually work. It took four weeks to get a reasonable map of the house. I have moved things in my house three times because we started learning over and over. The hardware is good - the sensors seem adequate but the AI and "smart map" are not smart enough. I plan to publish a more complete review with what I learned so the users of the Bot can build a knowledge base.