Eufy Omni S2 150-Day Review: Clever Cyclone, but a Mopping Downgrade

This unit was purchased for personal use, and this review is not sponsored, approved or otherwise affiliated with Eufy.

The Eufy Omni S2 has been in our home since its March relaunch, but repeated problems and the elusive hope that firmware updates might resolve our issues kept pushing this review back.

After roughly 150 days, plenty of cleaning cycles and multiple remaps, the picture is now clear enough that more time is unlikely to change the verdict on this product.

The Cyclone System Is the Highlight

The most interesting thing about the S2 isn't the mop.

Eufy's cyclone design helps separate debris before air reaches the robot's filter. It does a noticeably better job of preventing the filter from becoming packed with fine dust compared with more conventional robot vacuum designs.

That's a meaningful advantage, especially because clogged filters can quickly reduce airflow and cleaning performance.

It isn't maintenance-free, though.

Dust eventually builds up inside the cyclone itself, and after about 90 days, ours needed to be disassembled and thoroughly cleaned.

That makes Eufy's cyclone advantage much less clear-cut. Homes with heavy pet shedding will likely need to clean it more often, potentially every 60 days or so.

In practice, you're trading a filter blowout or swap every week or two for a more involved cyclone disassembly every two or three months. The maintenance is less frequent, but it isn't necessarily less work.

Better-Than-Average Carpet Cleaning

Carpet pickup is better than average, although it hasn't lived up to the level of performance suggested by Eufy's marketing.

The S2 generally handles everyday surface debris well and has plenty of suction for routine carpet cleaning but lacks the deep-cleaning ability of the Dyson 360 Vis Nav. Battery life is good, allowing it to cover larger areas without constantly returning to the dock.

The S2 can struggle with transitions onto certain rugs and carpets, sometimes getting stuck as its wheels make repeated adjustments while trying to navigate those areas.

Adjustments are surprisingly noisy, producing a mechanical sound that seems straight out of a "Transformers" film.

Another limitation is that maximum suction is reserved for carpet, leaving hardwood and tile with reduced vacuuming power. That noticeably hurt the S2 when picking up heavier debris such as cat litter and sand on hard surfaces.

Eufy's fragrance pods smell pleasant, but the effect is too subtle to count as a selling point.

The S2 Isn't a Better Mop Than the S1 Pro

Eufy says the S2 applies up to 15 newtons, or 3.3 pounds, of pressure through its roller mop.

But pressure alone doesn't make a good mopping system.

The bigger issue is water usage.

The S2 uses considerably less water than the S1 Pro, which hurts its ability to clean dried or more difficult messes. Despite the S2's higher mopping pressure, the S1 Pro still performs better in everyday use.

The extending roller doesn't help as much as expected, either. It frequently fails to extend, and even when it does, it doesn't reach as far underneath cabinets or furniture as the S1 Pro, even after setting the height-detection sensitivity to Breakthrough mode.

Maintenance is another step backward.

The reservoir's two filters are awkward to remove, and the metal pull tab on one of ours has already broken, forcing us to pry the plug out whenever the reservoir needs cleaning.

The redesigned reservoir uses a thicker scraper, in part to address dripping complaints associated with the S1 Pro, E25 and E28. But the scraper no longer pulls away from the reservoir, making the area harder to clean and adding maintenance difficulty without any noticeable improvement in mop roller cleanliness.

Solid Obstacle Avoidance, but Not on Carpet

Obstacle avoidance is above average on hard surfaces. The S2 can recognize and avoid many everyday objects reasonably well, including most cables, shoes, furniture legs and even some clothing.

On carpet, it becomes considerably less reliable, with the S2 frequently failing to identify clothing, shoelaces and even caster wheels on office furniture.

We've also found that our S2 unit stopped multiple times in doorway transitions where carpet meets hard flooring, for no apparent reason.

More concerning was how Auto Stain Cleaning performed. Eufy advertises the robot's ability to detect stains and shows it cleaning a ketchup-like spill, but the S2 failed to recognize similarly colored salsa that spilled on the floor in our home. Instead of identifying the mess and adjusting its cleaning behavior, it simply drove through it.

Owners in the Eufy Discord have reported the S2 failing to detect pet waste, and Eufy customer service has acknowledged that the detection algorithm is still a work in progress.

Navigation Feels Like a Step Backward

The original S1 Pro wasn't perfect, but its front-mounted spinning lidar gave it dependable spatial awareness.

One of the S1 Pro's biggest strengths was how well that navigation complemented the physical design. The slim, squircle-shaped body could reach beneath furniture and maneuver through tight areas around bathroom fixtures and under cabinets.

Unfortunately, the S2 doesn't feel as capable in those confined spaces.

It can struggle in dark rooms and is more prone to becoming confused or stuck. We've also had it repeatedly bump into doorframes and trim after missing a room entrance by just a few inches.

Its movement can look less controlled, too. Rather than tracking in a clean, steady line, the rear of the robot sometimes swings back and forth as the wheels make constant corrections, almost like a vehicle fishtailing. It usually works its way through, but the behavior feels noticeably less polished than what you'd expect from a flagship model.

Eufy's monthly firmware updates haven't always made things better.

During our first 150 days with the S2, software issues forced us to remap our home multiple times. That becomes especially frustrating after spending time editing rooms, creating cleaning scenarios and rebuilding no-go zones.

Automated schedules and cleaning tasks were also inconsistent after a remap. Sometimes they carried over and worked as expected, and other times they had to be recreated or simply failed to run.

The App Compounds the Problem

For a flagship robot vacuum in 2026, Eufy's app simply isn't on the same level as its competitors.

The most glaring omission is a dedicated mop-only mode. After years of Eufy positioning its roller mop as a headline feature, that's increasingly difficult to excuse, especially at this price.

More broadly, the app lacks the customization available from Dreame, Roborock, Ecovacs and Narwal.

There are only three water-flow levels for the mop: low, medium and high. Competing flagships typically offer much more granular control, often through sliding scales with dozens of adjustment levels. If you prefer to fine-tune water use for specific spills or messes, the S2 gives you very little control.

AI Automation does a good job of detecting floor types and adjusting cleaning strategies, but it isn't nearly as customizable as Narwal's Freo Mind or Dreame's CleanGenius automated cleaning modes.

There's also no option to follow the direction of the flooring, leaving the S2 to determine its own cleaning path. On our hardwood floors, cleaning perpendicular to the planks increases wheel noise and can leave debris and water behind in the seams.

Self-emptying controls are similarly limited, with intervals based only on 15-minute increments up to 60 minutes.

Map editing is above average, and automatic furniture detection is one of the better implementations on the market.

However, the app can also create phantom smart no-go zones and unnecessary stuck-carpet warnings that require manual dismissal after every run.

Those pop-ups are annoying, and they only add clutter to a map interface that could already use simplification.

A Nice Base Station With Some Compromises

The Omni station is sleek and relatively narrow, with a taller design that places the water tanks higher than many competing docks.

That's a practical advantage because it means less bending over when removing or replacing the tanks, and the station looks more refined than some of the oversized docks that now accompany flagship robot vacuums.

The trade-off is capacity.

The clean-water tank is smaller than those offered by many competitors, something that becomes more noticeable in larger homes or with frequent mopping.

Refilling that tank is only part of the running cost. Eufy also remains one of the few robot vacuum manufacturers using a nonrefillable, proprietary detergent cartridge. The S2's holds 330 milliliters for $22.99, while the S1 Pro's holds 600 milliliters for $32.99. That works out to 27% more per milliliter for the S2, and there's no option to refill the cartridge or use your own floor cleaner.

Support and Parts Availability

Replacement parts have also been hard to get.

While our bumper replacement was purely cosmetic and stemmed from scratches caused by our unit aggressively going under low-lying furniture with early firmware, it still took roughly three months for the replacement part to arrive.

Our issue didn't prevent us from using the S2, but a failure involving a more critical component easily could have.

That's difficult to overlook on a premium robot with so many moving parts. If even a relatively basic replacement part takes months to arrive, a more serious failure could potentially sideline the machine for an extended period.

To Eufy's credit, its customer support team stayed on top of the issue and sent periodic email updates about the part's availability and expected ship date, although most of those estimates were inaccurate.

We had several interactions with Eufy customer support over the past few months. During this time, the company appeared to lean heavily on AI-assisted troubleshooting before connecting customers with a live support representative.

In practice, that meant repeated emails about the same issues and going through similar troubleshooting steps more than once instead of quickly moving toward a resolution.

For a robot in this price range, the after-sales experience could have been smoother.

Too Many Compromises for the Price

There are things to like about the S2. Its cyclone design remains rare among robot vacuums, carpet pickup is better than average and battery life is solid.

The base station is also a highlight. It feels premium, handles a lot of the day-to-day maintenance automatically and is one of the more advanced designs on the market. The robot itself is slim enough to fit beneath low-clearance furniture that stops many competing models.

But those strengths are overshadowed by an ownership experience that has been consistently frustrating. The S2's navigation feels less polished than the S1 Pro's, software issues have forced repeated remapping, the app still lacks customization and maintenance has been higher than expected.

For S1 Pro owners hoping the S2 would be the obvious successor, it isn't. In several important ways, it feels like a step backward.

At this price, there are simply too many compromises and better options out there.

Skip it.