Review (1/5): Most of the brushes failed in two to three days
I got the factory rejects. Almost every single one of the brush heads failed within 2-3 days. Failure seemed to occurr at start up after a few on-off cycles. I think there must be an overshoot of the vibrator during start up. The vibration mechanism of the brush section is a thin metal piece that is attached to magnets and it seems to separate after a few operations.