Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Roborock - S8 Pro Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Battery life | 180 min | 200 min |
| Mopping | true | false |
| Lidar | true | false |
| Noise | 67 dB | 68 dB |
| Suction | 6000 Pa | 0 Pa |
| Water tank | 180 ml | 0 ml |
Between the S8 Pro Ultra and Roomba j9+, the S8 Pro Ultra comes out ahead in mopping / lidar, while the Roomba j9+ wins on battery life. Overall, the S8 Pro Ultra scores 79 and the Roomba j9+ scores 45.9 on our Mars Score.
Which should you buy?
The S8 Pro Ultra is the clear pick on raw spec strength, leading by 33.1 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the S8 Pro Ultra if you care most about mopping / lidar. The biggest gaps in its favor are mopping, lidar, noise, among others. The single most decisive one: Has Mopping.
Pick the Roomba j9+ if you care most about battery life. Its strongest claims are battery life. The single most decisive one: Battery life — 11.11% more. 200 min vs 180 min.
Both ship with comparable self-empty base, ai obstacle avoidance, so those specs do not separate the two — focus on the differences below.
Bottom line: the S8 Pro Ultra is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Roborock - S8 Pro Ultra or iRobot - Roomba j9+?
Roborock - S8 Pro Ultra leads the current Mars Score by 33.1 points.The more useful decision is the trade-off behind that result: compare suction, battery life, mopping against the way you will actually use the product.
Choose Roborock - S8 Pro Ultra if…
Roborock - S8 Pro Ultra has the measurable edge on has mopping, has lidar, noise db.
Choose iRobot - Roomba j9+ if…
iRobot - Roomba j9+ has the measurable edge on battery life min.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Roborock - S8 Pro Ultra wins
- ▲Has Mopping.
- ▲Has Lidar.
- ▲Noise — 1.00 dB less. 67 vs 68.
- ▲Suction: 6000 Pa vs 0 Pa.
- ▲Water tank: 180 ml vs 0 ml.
Why iRobot - Roomba j9+ wins
- ▲Battery life — 11.11% more. 200 min vs 180 min.
Spec comparison
Cleaning
| Spec | Roborock - S8 Pro Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Suction | 6000 Palead | 0 Pa |
| Mopping | truelead | false |
| Water tank | 180 mllead | 0 ml |
| Dustbin | 400 ml | 500 mllead |
| Carpet detection | true | true |
Navigation
| Spec | Roborock - S8 Pro Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Lidar | truelead | false |
| Camera navigation | true | true |
| AI obstacle avoidance | true | true |
| Max climb | 20 mm | 20 mm |
Autonomy
| Spec | Roborock - S8 Pro Ultra | iRobot - Roomba j9+ |
|---|---|---|
| Battery life | 180 min | 200 minlead |
| Self-empty base | true | true |
| Self-wash mop | truelead | false |
| Self-dry mop | truelead | false |
| Noise | 67 dBlead | 68 dB |
Frequently asked
Which has stronger suction, S8 Pro Ultra or Roomba j9+?+
S8 Pro Ultra delivers 6000 Pa vs 0 Pa.
Do S8 Pro Ultra or Roomba j9+ mop?+
S8 Pro Ultra mops; Roomba j9+ vacuums only.
Which has a self-emptying base, S8 Pro Ultra or Roomba j9+?+
Both ship with a self-emptying base.