Wolf, I can actually answer the question as we do have a robot vacuum cleaner(Roomba model). We just use it for our living room as that gets grubbiest apart from the kitchen which is just a quick and simple sweep. The robot is quite effective, we simply put all the floor clutter on the sofas(this isn't necessary but makes for a quicker and better job) and let the beast (cerberus)loose. It is very thorough, it remembers the layout of the room after a few passes so only bumps carefully into the fixtures, it covers the floor about four times and cleans under the sofas and when the battery is low it goes back to it's recharging point under an armchair.. No human would be as thorough, it misses nothing. It is really a matter of whether you think it is worth the money. It is a great boon when we have surprise guests as it can be left to do the cleaning whilst we get on with the food and drink preparation.