For comparison: the much more expensive Neato Botvac Connected and iRobot Roomba 980 collected only 50 and 60 grams, respectively. So this is an excellent result for a vacuum cleaner costing about 25 thousand rubles.
Better than before
The 900 series systematically covers the edges and runs along all the lines in the apartment. The 600 series of this technique is not enough. Instead, Roomba 681, as before, moves around the rooms, seemingly chaotically. However, the robot manages to achieve almost complete coverage of the area, even with a visit to the next room. The negative consequence of chaotic movement is the lengthening of the distance traveled: it takes about 30 minutes for the 681 to clean one room, while his more rational colleagues do the same job in less than 20 minutes. This also explains the greater amount of garbage removed: the robot can pass through the same place several times. However, the same effect can be forcibly achieved on more expensive models.
The rest of the navigation is also not the most thoughtful. Roomba can ride around a chair leg five times, bump into furniture loudly, and close doors. At the same time, he has no problems with cables. On the contrary, in the test room, he dragged a network extension cord with him, as if nothing had happened. Against all external circumstances, it independently returns to the charging station and uses sensors to recognize especially dirty places, which it then cleans more intensively in Spot mode.

Spartan and loud
As basic features, Roomba 681 offers the ability to program daily cleaning and manual Spot cleaning. This is good. The dust collector is disappointing here: it is half-open and practically not insulated. For allergy sufferers, this will be a real test. It will be very bad if you try to use the robot while you are at home. The little cleaning assistant makes a deafening noise. While cleaning on carpets, it can still be tolerated, but when it hits hard surfaces, the sound becomes similar to the work of electric garden shears.
Pros and cons
+ surprisingly good dust suction
+ few problems with cables and light carpets
— unacceptable volume
— chaotic orientation
— rough navigation
Alternative: Neato Robotics Neato BotVac 80
Wide brush, large trash can and smart navigation: although the Botvac 80 costs a little more, around 27 thousand rubles, but thanks to better navigation, it will not take forever to clean.
Conclusion
The Roomba 681 is a robot vacuum with decent suction power and not much extra functionality. During the suction test, the robot performed very well, picking up a fairly large amount of dirt. However, in terms of equipment and choice of accessories for its class, it offers only the necessary minimum. A particularly negative impression is produced by an unpleasantly high noise level.