Eufy S1 Pro Omni review: The best robot vacuum I've tested - but it comes at a price

It feels like we've reached a bit of a saturation point with robot vacuum cleaning tech. Now that pretty much all the premium models feature oscillating mop heads, smart base stations with dust removal and mop washing, and LiDAR mapping, it's hard to see where we go next.

And then Eufy comes along. I test a lot of robot vacuums throughout the average year, but the one I've been keeping in the corner of my living room for the daily grind has been a Eufy, for quite a long time.

The X8 Pro was a firm favourite until the X9 Pro came along. And then I curtailed a brief foray into iRobot ownership to welcome in the Eufy X10 Pro Omni. And I honestly didn't think it could get any better than that.

But here we are with Eufy's latest hero product, the Omni S1 Pro. And it's like no other robot vacuum out there.

First things first, it's an odd-looking thing. The robot itself has a squared-off look, which isn't incredibly unusual, but the base station is tall and narrow, rather than wide and squat, like the others we've been getting used to.

It also has a transparent tank at the top, with a second tank behind it. That front tank is a bit of a party piece, and I'll come back to that, but the base station also contains a bag to gather the dust in from the vacuum.

And then there's a mop-cleaning and drying system, and then there's a digital display on the top. It's all a bit mind-blowing at first, but it's a functional design and you get used to it very quickly.

Speaking of which, setting up the Omni S1 Pro is a doddle. It's easy to unbox, despite its height, and its relatively narrow base station slots neatly in the corner of a room. It's by no means innocuous, but I like it. It blends in better than I thought it would.

The EufyClean app, in case you've never been acquainted with it, is superb. Setting up maps is a bit fiddly, but in all other ways, especially the initial setup, it's just really well thought out.

Setting the Omni S1 Pro out on its first mapping run is a completely effortless affair. I've never known a robot vacuum do such a short sweep and come back with an immaculate map. There's no two ways about it, this has the best sensors in the business.

And that's a big help when it goes out on its first cleaning run. It very quickly identifies what surface it's cleaning, and it adapts automatically, ensuring it's always in the optimum mode.

At first, it will miss out on the very edges of the room, but a few more runs is all it takes to get to know your nooks and your crannies, and it figures everything out very well.

It copes well with uneven surfaces and thresholds, too. There's a lot of power in its motors, and it feels like a plucky little fellow, so getting up on to thick rugs isn't a problem, and my chunky room dividers weren't much of an issue either.

Battery life is perfectly acceptable, as is the size of its on-board tanks. It can complete a sweep of my downstairs in its most attentive modes without having to refill the water or empty the dust tank, and there aren't many robot vacuums that can do that.

And when it returns to the base, it'll empty the dust tank and wash the mops. This is when the magic happens.

Like its predecessor the X10 Pro Omni, it uses hot water to wash the mop heads. And dirty water is captured in a separate tank. Also like the X10 Pro Omni, it then dries the mop head. This takes a frustratingly long time, but it's a quiet process and there's a neat progress bar on the display, which is handy.

Unlike the X10, however, is a very clever system built in that "ozonates" the water. There's fancy lights in the tank so you can see it all happening. I did read up on why this happens, but I'm honestly not clever enough to understand the benefits.

What I can say, however, is that the mop head comes out remarkably clean and bone dry, so it obviously works.

It is a pity, though, that the cleaning fluid now comes in a disposable bottle that slots in to a set cavity in the base station. Of course, Eufy insists you only use its own fluid, but now you're basically forced to. The bottle isn't refillable and there's no getting away with using a cheaper third-party cleaning agent. Spoilsports.

Beyond all this oxygenating and theatre, there doesn't appear to be a lot to physically differentiate between this new Omni S1 Pro and the X10 Pro Omni. And that's quite alarming given the X10 costs £799, while the S1 costs £1,499. However, if you flip it over you'll notice one fundamental difference straight away. The Omni S1 Pro has a rolling mop. Unlike the X10's pair of round, oscillating mops, this new cylindrical mop makes a firm contact with the floor, and it's constantly being cleaned by the on-board tank.

One of the issues I had with the X10 is that, on a long cleaning stint, the mops did get a bit mucky and the floor started to streak. But this simply hasn't happened with the S1. As a robot mop, it is utterly remarkable.

And as a vacuum it performs slightly better too. It's not a startling difference, but it really is noticeable. Its squared-off shape helps it get into corners, too.

Beyond these benefits, the differences are more subtle. And that makes it easier to be shocked at the differences in price between the two Eufy hero products.

But in just about every measurable way, the Omni S1 Pro is at least a little bit better at the job. It feels more special, more like it's been fettled with until the point of perfection, and more likely to perform better every time, and for a longer time.

Yes, it's expensive. Yes, it has divisive styling and, yes, some of its features might give off a function-over-form vibe, but I honestly haven't found a better robot vacuum, when all's said and done.

Eufy has done it again. In the face of increasingly stiff competition, they've created a unique, interesting, likeable and, incredibly functional robot vacuum that does everything it's supposed to do incredibly well.

I'd be very surprised if they manage to top this with any successors in the future, but I have a feeling they'll find a way. They always do.

This article has been updated to reflect current pricing.