I bought this one because my couch has 3.4 inches of clearance underneath and every other robot vacuum I've tried has bonked its lidar tower into the frame and given up. The Saros 10R goes under it. The tower retracts when it senses a low overhang, the robot drops to 3.14 inches, and it cleans the part of my apartment that has never been cleaned by anything but a yardstick wrapped in a sock. That alone justified the purchase for me. Whether it does for you depends on your couch.
The rest of the robot is a Roborock flagship, which at this point is a known quantity. The lidar mapping is fast and accurate; the apartment was mapped on the first run and the room divisions were correct enough that I only renamed two. Suction is rated at 22,000 Pa, which is a meaningless number from a meaningless arms race, but in practice it pulls cat litter out of the deep edges of the kitchen rug in one pass. The brushes are dual rubber rollers, no bristles, which means far less hair tangling. I've owned the robot four months and have not had to cut anything out of the brush bar.
The mop is the part Roborock has built its reputation on, and it is still the part it does better than anyone else. The Saros 10R uses dual spinning mop pads with downward pressure that the robot can lift over carpet. It mops the kitchen tile well enough that I no longer mop it manually except for sticky spills. The dock hot-washes the pads at 60 degrees Celsius between runs and then dries them with hot air, which sounds like overengineering and is the thing that has kept my robot from smelling like a wet rag for the first time ever.
The app is good but busy. Roborock's interface assumes you want fine control over twenty things, and it is correct that you can have it, but the defaults are not as well-tuned as iRobot's. I spent about an hour the first week setting up no-go zones, mop-only zones, and per-room suction levels. After that, it has been hands-off.
The catches. The Saros 10R is loud — not painfully, but noticeably louder than the j9+ at the same suction level. Obstacle avoidance is better than last year but still occasionally eats a charging cable; I have lost one. The dock is bigger than iRobot's and harder to hide, which matters in a small apartment. And the value proposition pushes you toward a $1,599 bundle for the full self-cleaning dock; the cheaper version requires you to handle the dirty water yourself, which defeats the point.
The other thing worth knowing: Roborock pushes firmware updates aggressively. Mine has improved at things I didn't ask it to improve at, and once, briefly, regressed on something I did want it to do. The improvements outnumber the regressions, but you are along for the ride.
At around $1,600 for the full bundle, the Saros 10R is more expensive than the j9+ and more capable on paper. Whether you'll feel the difference depends on the apartment. If you have lots of low furniture and you'd rather your robot mopped seriously than vacuumed politely, this is the one.
Verdict: Buy this if you have furniture nobody else's robot fits under, or you want a robot mop that actually mops.