Both the Roborock S8 MaxV Ultra and Roomba j9+ claim to avoid obstacles, and both are pretty good at it. Neither is perfect. If you're expecting a robot that never hits anything, you'll be disappointed by both.
What's Under the Hood
The S8 MaxV Ultra uses 3D sensors plus an RGB camera. It recognizes 73 different object types: shoes, cables, pet waste, toys, and more. The 3D sensing provides depth perception.
The Roomba j9+ uses PrecisionVision Navigation. iRobot specifically trained their system on pet waste recognition, which is smart because that's the obstacle nobody wants their vacuum to "discover" the hard way.
Real-World Performance
Both Handle These Well
- Pet waste
- Shoes and slippers
- Power cables (usually)
- Pet toys
- Furniture legs
Where Things Get Messy
The Roborock sometimes:
- Eats extension cords despite "seeing" them
- Gets confused by wool and certain fabrics
- Inconsistently recognizes socks
The Roomba sometimes:
- Bumps obstacles before recognizing them
- Struggles in the dark
- Gets confused by mirrors and shiny surfaces
The Pet Waste Question
If this is your main concern, the Roomba j9+ has a slight edge. iRobot offers their "P.O.O.P" warranty that specifically covers pet waste incidents. They've trained their AI specifically for this scenario.
The S8 MaxV Ultra detects pet waste too, but it's part of a general obstacle avoidance system.
The Bottom Line
For typical obstacle avoidance in a reasonably tidy home, both work fine. For pet owners specifically worried about accidents, the Roomba's dedicated warranty gives more peace of mind. For general cluttered-home situations, it's essentially a tie.
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How we researched this
Where this comes from: this answer draws on the product's published specifications and the reviews ShopSavvy collected for it, alongside prices from ShopSavvy's price data.
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