The s9+ D-shape means it actually reaches corners

Most robot vacuums are round, which means they leave a crescent-shaped gap in every corner. The s9+ is D-shaped — flat on the front — so its brush reaches all the way into the corner where wall meets wall. That one design difference makes it the best Roomba for edge cleaning by a noticeable margin.

Beyond the shape, the s9+ also has superior suction and smarter pathing. It rows in straight lines rather than bouncing around, which means edges get cleaned systematically rather than by luck. If corner dust bothers you — and it should — the s9+ is the only Roomba that genuinely solves the problem rather than claiming to.