We got a Roomba. First: it is good at cleaning, and is less noisy than a vacuum cleaner. Those are really the things that matter in such a product. It gets underneath furniture, and cleans places that we normally don't clean. Places like the Living Room, Kitchen, Family Room, Bathroom, Office, and the Bedrooms.
Supposedly, the Roomba doesn't generate a "mental map" of its area, it just uses a procedural system to clean at "semi-random". I call shenanigans. The Roomba does make a map, and it uses it to frustrate your attempts to get it to do what you want.
When we first set it up, it was next to the entryway, so it wasn't surprising that it ended up hanging out there, and seeming sort of "stuck" in the entryway. We moved it to the other side of the house, and it quickly recognized that fact. It scouted around for a minute, then quickly returned to the entryway.
Another time, I pressed the button that told it to return to its Dock, where it recharges. It promptly went to the place in the house farthest from the Dock, and only grudgingly left that room, only occasionally briefly issuing out to trick me into thinking it was going back to the Dock. To be fair, it did make it eventually.