The Roomba Combo j9+ ($1,399) is the best robot vacuum iRobot has ever made — and the best robot vacuum for carpet-heavy homes, period. But Roborock has caught up and surpassed iRobot in almost every other category. After 45 days of testing, here is where the j9+ still wins, and where it falls behind.
Key Specs
| Spec | Roomba j9+ | Roborock S8 MaxV |
|---|---|---|
| Suction | Not published | 8,000 Pa |
| Navigation | Camera vSLAM | LiDAR + Camera |
| Mopping | Drag pad + retractable arm | VibraRise 3.0 vibrating |
| Self-Empty Dock | Yes (bagged) | Yes (bagged) |
| Obstacle Avoidance | Yes (camera-based) | Yes (Reactive AI 2.0) |
| Pet Waste Guarantee | Yes (P.O.O.P.) | No |
| Price | $1,399 | $1,799 |
Where the Roomba Wins
1. Carpet Deep-Clean Is Unmatched
iRobot's dual rubber extractors are the best in the industry at agitating carpet fibers. In our embedded-dust carpet test, the j9+ visibly outperformed every Roborock model — after a single pass, the white-glove test showed noticeably less residual dust than any competitor. If your home is 70%+ carpet, this matters more than any other feature.
2. The P.O.O.P. Guarantee
iRobot will replace your robot if it runs over solid pet waste within the first year of ownership. No other brand offers this. For dog owners who run their robot while away from home, this is genuine peace of mind. In our tests, the j9+ correctly avoided our fake pet waste 8/10 times — good but not perfect. The Roborock S8 MaxV scored 10/10.
3. iRobot OS Learns Your Home
The j9+ identifies the dirtiest zones in your home over time and auto-targets them for extra passes. It also suggests "Clean Zones" — areas like in front of the couch or near the back door where dirt accumulates. After 2 weeks, it was correctly prioritizing the entryway and kitchen, where our home accumulates the most debris.
4. Edge Cleaning Is Excellent
The corner brush design on Roombas is still better than Roborock's. The spinning side brush reaches deeper into corners and along baseboards, and the j9+ has a specific "edge clean" behavior where it follows walls with extra precision.
Where the Roomba Falls Behind
- Navigation is slower: Camera-based vSLAM takes 2-4 full cleaning runs to generate a complete map, vs Roborock's LiDAR which does it in 8 minutes. The j9+ also bumps into furniture more during the learning phase and requires lights on to navigate.
- Mopping is basic: The retractable mop arm is clever — it lifts the pad entirely on top of the robot for carpet — but the mopping itself is a damp cloth being dragged. It does not scrub. Dried stains will remain.
- App is less polished: iRobot's app has improved but still suffers from connection issues and occasional lag. Roborock's app is faster and more reliable.
Our Verdict: Buy It for Carpet, Skip It Otherwise
If your home is mostly carpet, the Roomba Combo j9+ is the best robot vacuum you can buy. Its dual extractors clean deeper than any competitor, and the P.O.O.P. guarantee is unique. But if you have mixed flooring, want real mopping, or value fast navigation, the Roborock S8 MaxV Ultra or Qrevo Master are better choices — and the Qrevo Master costs $300 less.
Rating: 8.7/10
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