Here's my Amazon.com Roomba review [3 stars out of 5 possible]:

We recently tried Roomba, but returned it: too much overhead. Roomba seemed to perform as advertised, and it's certainly fun to watch. However, in our particular situation, we couldn't justify its cost. Its limitations prevent any savings in time or effort. Under the right circumstances, however, Roomba is probably worth having.

Overall, there's just too much pre-Roomba prep work (setting virtual walls, picking up small rugs, taping down electrical cords, shutting doors) that has to happen each and every time Roomba runs. We also have too many nooks and crannies and carpeted rooms that will have to be cleaned by traditional vacuum anyway that Roomba's price and demands just don't justify themselves.

Theoretically, it might be possible to set up virtual walls permanently, but maybe not. If you place them on the floor, they're another thing to trip over and collect dust. If you can somehow mount them off the floor so they're still effective, they'll still have to be dusted. If you don't leave them set up permanently, then you have to set them up each time Roomba runs, which is counter to Roomba's convenience factor.

In our experience Roomba could not handle a very flat rug, toilet carpet, and bath mat. The latter two are probably too thick for it, but the flat one should have been no problem at all. It had very low pile, and even small rubber tapered edging that should have helped Roomba, but Roomba kept catching an edge and having difficulties with it.

Pre-Roomba house preparation includes securing electrical cords along baseboards, which is fine if it's a one-time need, but we have a couple lamps we move around the room to vary lighting, and so the need to ready them for Roomba's efforts each time work against the convenience factor. Plus there's Roomba's own cord and docking station to deal with, securing and dusting, and finding an unobtrusive place on the floor where it's simultaneously out of the way but accessible.

Finally, we have too many rooms with carpet that Roomba cannot handle, so we have to go around closing doors to keep Roomba out (and remembering to do so before it's schedule to run). Add this perhaps trivial chore to all the other overhead, and it's just easier to lug out the traditional upright vacuum cleaner to sweep the house. With a traditional vacuum cleaner it's easy to just do one room after another, sweeping around cords, rugs, etc.

As for Roomba overhead, you also have to empty its dust bin and clean the rollers periodically. None of my criticisms should be taken as complaints. I merely want to stress that Roomba may not really be as convenient as one might hope or expect. If you have accommodations that work well with Roomba's limitations, it may serve perfectly well. If you're like us, however, sticking with the tried and true will see you through.

We would buy and keep a Roomba, perhaps two, if it could handle deep-pile carpeting and had less obtrusive virtual walls. (One of the reasons the virtual walls units appear to be so big is that they use D batteries; can't these units be made to run on a smaller power source, perhaps one small enough to stick to a door jamb with a piece of Velcro?) Best of all would be a way to create a map of our house and upload that into Roomba, and specify cleaning limits and times for different areas. If we had that functionality, there wouldn't be as much need for it to handle the carpets in our house.