The other primary difference here is aesthetic. iRobot has simplified the design scheme to make using the cleaning bot as simple as possible -- and really, gadgets don't come much more simple to operate than the Scooba. You open it up by pressing down and pulling up the big, clearly marked handle. Stick some of the cleaning solution into the clean tank -- delineated by the bright blue rubber "Clean" tab (not to be confused with the dull gray "Dirty" one) -- and fill the rest up with water. A full tank should last you about 45 minutes worth of scrubbing.
The Scooba's got a few levels of cleaning protection on the bottom -- it sucks up small debris into its tank (for the full vacuuming deal, iRobot still recommends the Roomba), washes the floor with a small amount of cleaning solution, scrubs the surface with rotating bristles and then a thin squeegee-like apparatus sucks up the rest of the liquid dirt. The front side of the Scooba is a fashioned into something of a bumper, so the 'bot can lightly bang into walls to find its way, readjusting itself in the process. The Scooba also ships with a Virtual Wall device, which runs on D-sized batteries (the Scooba itself has one giant
The Scooba's cleaning pattern is fairly unpredictable. According to iRobot, it chooses one of three patterns: wall following, spiraling and room crossing -- all are pretty much what they sound like on paper. We dumped some liquid on the ground and waited around for what seemed like forever trying to get the 'bot to hit a particular spot on the floor. The watched Scooba never mops -- not where you want it to, at least. It took some time, but the Scooba finally hit its mark, cleaning the spill, but leaving a damp floor in its wake.