Four Stars
So far these are performing well and seem as sturdy as the original toothbrush from Philips Sonicare.  The only reason I don't give a 5 star is because this toothbrush doesn't have the indicator color to let you know when you need to replace toothbrush and it does not come with a toothbrush cover like the Philips sonicare product does.
Rating: 4 stars