Review (5/5): So far so good!
Until Sonicare decides to lower their price-point on replacement brush heads, I will continue to buy these generic ones. I was a little wary of buying them after seeing the other reviews containing snapped off brush heads; missing bristles; etc. However, mine came in brand new condition with intact, soft bristles. They work exactly the same as Sonicare.
** 1 month update: The replacement head is still working as it should. No bristles falling out or snapped stem.