In my case very good product.

This robot exceeds my expectations.
I have no carpet or carpet tile floor, but only a lot of corners, furniture including two diametrically opposite to the main room and a hallway.
Robots random movement worried me to be able to go all round, hence my choice.
It's amazing to see him work. It performs a first path according to a predefined patterns, then it goes directly from its final position to an area "forgotten", and then to the next, etc ...
The collection is not perfect, a Roomba is certainly better among other because it passes several times in the same place, but it is easy to launch the "manually" before work and schedule a daily pass and 2 passes are made for a better result.
It is very quiet, I'm running in the morning when the small are still sleeping, for he needs against the light to work if the camera can not be mapped. In normal mode, it slowed down when approaching a big obstacle (wall, sofa, big pot, stops at the distance corresponding to the length of his little broom and turns sweeping the board.
The "suction power" seems limited, there has a function "max" but I would have reservations about the effectiveness on a rug or carpet. It's more a brush that picks up a vacuum cleaner.
However, the motor is good and proper crossing (it rises on a footing of 1.5 cm cabinet but it does not go up the stairs to make the rooms !!! ;-)