This one builds up a pretty darned detailed map of your home. (I've even noticed that it seems to know about the molding around closed doors, and when it passes such an area, it checks to see if the door is still closed, it is clearly trying to learn or escape...)
With the map, you can just speak to it and tell it what room to wander off to, no special devices needed.
The empties-its-own-bin feature is a total gamechanger, even though it condemns you to purchasing the little bags for the bin-emptying-machine about once a month. (I suspect I can re-use the bag if clever though, or that someone will soon produce an aftermarket reuseable bag.)