I would have given it 10 stars if possible.  The power is great the cups are a good size.  The only problem is locking it into position.  It doesn't lock if I have the cup attached to the blade for whatever reason. I attach the blade then I have to screw in the cup by turning the base onto the cup which is not always easy.  Yes I could return it but it seems that this is the only way because I can see the pin coming up through the rubber....that is why it doesn't lock in place properly.  I still love it.