My only complaint is that we only have one.
Rosie, our Neato robotic vacuum, has been doing a great job of keeping the floors vacuumed in the rooms where she runs. I still haven’t done anything to the living room to keep her from getting hung up on the coffee table, but I’ve turned her loose in there once or twice anyway. Once I used the magnetic strip to keep her out from under it, the other time I flipped it (the table) on its side.
The family room and upstairs, though, are now getting vacuumed a couple times a week. I am always amazed at the amount of crud that comes out of the carpet even when it seems clean. I’ve only had to intervene a couple of times when something got left on the floor (like a blanket) and sucked up, or once when the bot got hung up on a lamp base. Overall — well worth the money. I empty the dust bin after each run and occasionally vacuum off the paper filter; I just replaced it for the first time. It came with 4 spares, and it looks like they only cost 3-4 bucks each. Not bad if it means having your carpet vacuumed regularly.