So I bought one of these less than a year ago. It works ok, but it really is stupid. Low IQ stupid. It will back itself up into a corner or against a piece of furniture and rather than go forward, it keeps trying to back up. It finally dies and starts beeping. When I run it, I must “save” it every 10-15 minutes. As these are refurbished, perhaps I got a more mentally challenged one.
The one we picked up here on the last sale has worked ok considering most of our house is low carpet. It is rather dense and wanders around randomly but eventually everything gets cleaned up pretty good considering. It does get caught up in any cords we forget to pick up or area rugs as well but some times it figures it out and gets free on its own. On our vynil floors it does a great job and has cleaned up all the fine dust I get all over the place in my bathroom. It also did a great job on the entry way my parrot lives on and picked up all the bird food and crumbs he drops all over the floor as far as it could reach. Of course it terrified my parrot so I let him out to hang out with me in the other room, problem solved.
If you have mostly carpet the N79 version has a powered brush roll and hopefully Woot will get those eventually but it has worked ok for me for the great price paid.
Mine is now dead