I need to downgrade the rating from 5 to 3 stars after 2  months of usage. There is a design issue on the four little wheels at the bottom of the mopping module. Dust can be caught up on the axle of the wheels easily which ends up paralyzing the movement. To clean it up, you need to have a fine tweezer reaching to less than 2 mm gap. Since I vacuum every day, it becomes a hassle cleaning up every other day. And it will take 10-15 minutes to do it.