If you’re in the market for a robot vacuum and want to invest in the best, you are probably considering the iRobot Roomba S9 and roborock S4. Based on our rating, both robot vacuums have the same overall rating of 9.
A noticeable difference between two models is the size, which is 30.9 x 8.8/12.2 x 3.5 (D x H) cm/inches for the Roomba S9 and 35 x 9.1/13.8 x 3.6 (D x H) cm/inches for the S4. The weight of the Roomba S9 is 3.6/8.1 kg/lbs, and for the S4 it is 3.1/7 kg/lbs.
The iRobot Roomba S9 is better robot vacuum in this comparison. Check iRobot Roomba S9 price