I have one. Use it mostly on the main floor hardwood, thought does ok on hallway runner carpets.
Mine I found in a dumpster, and already had a spare new battery from another earlier dumpster find sitting out in the garage.
I had to disasseble the vac motor to clear an error code. It uses current draw on vac motor to signal dirt box is full. Oiled the shaft bearings with a drop each of light oil and it is now happy.
Plus I had to wipe dog hair oil out of where a LED send/receiver looks for dirt in the box.
Other than that, I pick up a bunch of chairs and set them on tables and then turn the thing loose, usually when out to get groceries, etc.
Works as advertised and the zero dollar price of mine makes it cute to use.
Often it goes back to base with a full cannister, so it finishes the job once I empty that out.