Roborock is one of the more expensive robot vacuum makers in the market — putting it in competition with iRobot's Roomba and also Ecovacs smart vacuums. Both its S6 Pure and S5 Max robots are priced similarly, with the S6 Pure at $499.99 and the S5 Max at $599.99. To make things even more complicated they share almost all of the same features including working with Amazon Alexa. So which one should you pick?

There is one main difference between the Roborock S6 Pure and the S5 Max — and here's how to tell which robot vacuum you should pick up based on your needs.

The Roborock S6 Pure has a mopping cloth that can be added to the base of the robotGearBrain

S6 Pure

The S6 Pure, which GearBrain reviewed, by virtue of its number, sounds like the most advanced robot vacuum from Roborock. But in truth both the S6 pure and the S5 Max share a lot of the same abilities.

With the S6 Pure you can schedule the robot in the Roborock app when you want it to run. You can also virtually map off areas where you don't want it to operate, once the vacuum has mapped your home.

The S6 Pure can also pair with Amazon's smart assistant Alexa, meaning you can set it on its way without going into the app, and just speaking aloud through an Alexa-enabled device. (Check out The GearBrain, our smart home compatibility checker to see the other compatible products that work with Amazon Alexa enabled devices.)

The S6 Pure also has a mop attachment — which means not only does it vacuum up floors, it can wet clean them too. The attachment doubles as water tank and can push a wet pad along a flat surface once that cloth is connected.

Roborock S6 Robot Vacuum, Robotic Vacuum Cleaner and Mop with Adaptive Routing,Multi-Floor Mapping, Selective Room Cleaning, Super Strong Suction, and Extra Long Battery Life, Works with Alexa(White)

List Price: $649.89

New From: $649.89in Stock

The Roborock S5 Max has a water tank that's much larger, increasing its mopping abilityGearBrain

S5 Max

Like the S6 Pure, you can schedule the S5 Max, which GearBrain reviewed, to clean, map off areas in the app where you don't want it to go, connect to Amazon Alexa so the robot can be controlled via the smart assistant, and also attach a cloth to the bottom of the robot so it can mop up floors.

The difference between the two is here — in the ability of the robots to mop. The S5 Max has a much larger water tank, 180 ml on the S6 Pure vs 290 ml on the S5 Max. That means more water can be pushed out of the robot to better clean up dirt that may be dried on the surface.

The water tank is also part of the S5 Max, rather than an added element, although robot vacuums need to have the cloth attachment snapped into place before they can mop.

The larger water tank can also be controlled through the Roborock app — something that the S6 Pure doesn't allow. There are four settings in the S5 Max side of the app, which let you shift between no water and heavy water use.

The Roborock S5 Max (on the left) has extra controls in the app to customize the mopping featureGearBrain

Which is the better robot vacuum?

The better robot vacuum is the one that works best for your space. If you heavy a lot of wood floors, and they see heavy traffic, the S5 Max may be the way to go here as it can handle mopping better, in our tests, on flat surfaces.

If your home has more carpeting, and you rarely mop or you are more likely going to mop or clean your floors on your own, the S6 Pure is a great option. Without the internal water tank, you're also less likely to have water dripping out inadvertently from the robot while it's sitting on the charger. Both the S5 Max and the S6 Pure do come with a plastic mat to place next to the charger to prevent water from accidentally sitting and damaging surfaces. But that need is certainly reduced with the S6 Pure.

The S6 Pure is also about $100 less than the S5 Max — so if you don't need the mopping feature, and you are looking to save a little, then that's something to consider. Then again, for $100 more you do get the same strong vacuum, with the option to use the solid mopping feature of the S5 Max. The choice, then, is yours.

Roborock S5 MAX Robot Vacuum and Mop, Robotic Vacuum Cleaner with E-Tank, Lidar Navigation, Selective Room Cleaning, Super Powerful Suction and No-mop Zones

Roborock S5 MAX Robot Vacuum and Mop, Robotic Vacuum Cleaner with E-Tank, Lidar Navigation, Selective Room Cleaning, Super Powerful Suction and No-mop Zones

List Price: $609.99

New From: $609.99in Stock