I finally ordered a Roomba on Sunday, and it arrived in the city yesterday, so I picked it up this morning.
First impressions are pretty good. It's pretty much as you'd expect (charge it up, turn it on, press "clean", and it goes around the room vacuuming), though it's mesmerizing to watch. I think the dust bin will be impressive to check out after a bit, it's probably full of decade-old dust, especially since I threw out all my old school notes that were rotting underneath my bed and let it rip under there.
Judging from the carpet in its wake, it seems as good as our (non-robotic) vacuum, and it's managed to pick up shredded paper bits and hair that I deliberately threw on the floor so I think it'll be fine. Even though I don't do the housework around here, this robot guy is very welcome.