It makes sense comparing iRobot Roomba i7 7150 vs iRobot Roomba S9 because they both are able to give some premium features. Based on our rating, Roomba i7 7150 has the overall rating of 7.7 out of 10 versus 9 for Roomba S9.
A noticeable difference between two models is the size, which is 33.7 x 9.1/13.3 x 3.6 (D x H) cm/inches for the Roomba i7 7150 and 30.9 x 8.8/12.2 x 3.5 (D x H) cm/inches for the Roomba S9. The weight of the Roomba i7 7150 is 3.3/7.4 kg/lbs, and for the Roomba S9 it is 3.6/8.1 kg/lbs.
The iRobot Roomba S9 is better robot vacuums in this comparison. Check iRobot Roomba S9 price