I have been using the other battery powered brand for over a decade, and decided to try the Sonicare Xtreme.  This model cleans better, and is easier to use.  As far as the leakage - the bottom is sealed by an "O-ring" (black plastic ring on the bottom).  To keep this seal intact and working, smear a SMALL amount of petroleum jelly on the O-ring all around.  This, plus some common sense care has kept our two Sonicare toothbrushes dry and corrosion free.