Don't waste your money...I bought a Roomba, and it is a piece of junk. I have mostly ceramic tile..
floors, but it can't handle different floors like area rugs and carpets, especially if the rugs have fringe, and you spend as much time cleaning the machine after you use it as you would vacuuming. You also have to pick up and move stuff that would get in the way of it vacuuming the whole room, i.e.tables and chairs, wastebaskets, etc.
I also made the mistake of buying the floor washer, the Scooba. It is a joke! I used it once. The floor was not clean, the floor was still wet, and it can't do nooks and crannies and edges, which is the same problem with the Roomba. And you have to move stuff out of the way for it to do its job. Don't waste your money on either one.