This is our second iRobot (first was an s9+). This is considerably quieter while vacuuming -- we briefly wondered if the vacuum part was broken when it went on its first cleaning run, but it quickly became clear that it was indeed cleaning. This model is also smarter than the s9 about navigating around furniture, avoiding dangling cords and shoelaces, etc. We've still had to rescue it a couple times when it got caught in some furniture (it loves to get trapped in the chair and table legs of the dining room set) but it recovers well after we give it a hand. Solid purchase.