Review (4/5): Works good...
I started using this product after my rechargeable Sonicare finally died (after four/five years). I have had this toothbrush for over a year and it works just as good as the rechargeable version. This unit is much more mobile because of the battery power, can be taken easily on travel trips, is cheaper than rechargeable version, and brush heads are easily found (best price at big warehouse stores).
As for other review comments, I have not had any problems with water getting in the battery compartment.