i think iRobot is one of the first company for these products .... since popularity is picking up with korean, japanese, china brands ....you won't go wrong with that. On the other hand, never tried the other brands .... they can be as good since really, there isn't any rocket science technology behind this products. i chose roomba mainly because of looks and colour at the point of time its a good helper ..... but you have to make some adjustment to your furniture (raise the sofa to make sure the robot can go under) consider the area of operation (may require additional virtual wall if you have stairs ... indoor pond ... etc) electrical cords is a headache (make sure to hide them well in case the robot 'trips over them' - usually it gets stuck there til no battery) back to using the broom and hand-held vacuum ... opportunity to burn some calories for the workout.