Is the Roborock S8 Pro Ultra worth the extra £200 over the Roomba j7+ used?

Yes, if mopping is a requirement. The S8 Pro Ultra adds active mopping with an auto-lift mechanism that raises the mop pad when it detects carpet, plus a dock that washes and dries the mop heads autonomously. If you do not need mopping and primarily have carpets or a pet household, the j7+ performs as well as the S8 Pro Ultra on vacuuming alone and costs significantly less used.

Which is better for pet owners — Roborock S8 Pro Ultra or iRobot Roomba j7+?

The iRobot Roomba j7+ is the better choice for pet owners. Its PrecisionVision camera-based obstacle avoidance was specifically trained to identify and avoid pet waste — a unique capability at this price point that the Roborock S8 Pro Ultra does not match. The j7+'s 8.7/10 bench score was achieved in a two-dog household with daily use over twelve months, making it the most directly validated option for pet environments on the Robot AutoTrader platform.

Do both models hold their value well used?

Both are depreciating at a similar pace. The Robot Resale Index shows the S8 Pro Ultra at 91.8 (down 8.2% year on year) and the j7+ at 93.2 (down 6.8% year on year). The j7+ holds value slightly better, likely because the j7's obstacle avoidance generation retains relevance longer. Neither is an appreciating asset — both are best bought used and replaced with a new model in two to three years.

What is the most important thing to check on each model used?

For the Roborock S8 Pro Ultra: confirm the full RockDock is included and run a complete self-wash cycle before buying — listen for pump noise and check the water lines. Without the dock, the listing should be priced well below £400. For the Roomba j7+: confirm the Clean Base dock is included, and check the PrecisionVision camera lens for cloudiness or scratches. A fogged lens is a £60–£80 repair.

Robot vacuum comparison

Roborock S8 Pro Ultra vs iRobot Roomba j7+ — Which to Buy Used?

Last updated 25 August 2026

The Roborock S8 Pro Ultra and iRobot Roomba j7+ are the two most bench-tested used robot vacuums on the Robot AutoTrader platform. They score 9.1 and 8.7 respectively — but they are designed for different households. The S8 Pro Ultra is a full vacuum-and-mop system with an autonomous dock; the j7+ is a vacuum-only machine with best-in-class obstacle avoidance for pet homes. The used price gap is around £200–£300, and choosing the wrong one for your floor type is a real mistake.

Robot vacuum & mop

Roborock S8 Pro Ultra

Used price (UK)£580–£720

Retail (new)£1,099

Bench score9.1 / 10

Resale index91.8(-8.2% YoY)

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Robot vacuum

iRobot Roomba j7+

Used price (UK)£340–£430

Retail (new)£549

Bench score8.7 / 10

Resale index93.2(-6.8% YoY)

Full price guide →

How they compare

Aspect	Roborock S8 Pro Ultra	iRobot Roomba j7+
Type	Robot vacuum + mop✓	Robot vacuum only
Bench score	9.1 / 10✓	8.7 / 10
Used price (UK)	£580–£720	£340–£430✓
Retail price (new)	£1,099	£549✓
Dock system	Full RockDock — self-empty, self-wash, self-refill✓	Clean Base — self-empty only
Obstacle avoidance	AI-based, good but not pet-waste specific	PrecisionVision camera — designed to avoid pet waste✓
Mopping	Active mop with auto-lift on carpet✓	None
Best for	Hard floors, mixed hard/rug, mopping required	Pet households, carpets, obstacle-heavy rooms
Best buy month	September	August

Which should you buy?

Choose Roborock S8 Pro Ultra

Choose the Roborock S8 Pro Ultra if your home has significant hard floor area, you want the mop function, and you are prepared to pay £580+ for a dock that genuinely handles itself. It is the better machine overall and the right choice if mopping is part of your requirement.

Choose iRobot Roomba j7+

Choose the iRobot Roomba j7+ if you have pets, particularly if pet waste avoidance matters to you, or if your budget sits under £450. The j7+ is a more focused machine — vacuum-only — but its camera-based obstacle avoidance is the best consumer implementation available used at this price.

Bottom line

For a mixed hard floor and carpet household without pets, the S8 Pro Ultra wins on performance and convenience. For a pet household on any floor type, or any home with a tighter budget, the j7+ is the smarter used buy.

For sale now

Roborock S8 Pro Ultra

£580–£720 used

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iRobot Roomba j7+

£340–£430 used