Unfortunately, my wife and me but now failed the third toothbrush. The vibration diminishes abruptly, probably a part is in the toothbrush broke due to vibrations. All three toothbrushes, this effect occurred shortly after might invalidate its warranty on (2 years).
Priced at EUR 120 for the set, this means 5 EUR costs per month - not counting replacement heads. For this reason I can not give more than 2 stars of the toothbrush.