Works great, but needs extra care to prevent failure [SEP] OK, same complaint as everyone else.  My first unit died in less than 2 months from water seepage into the battery and switch compartments.  That being said, it does an excellent job of brushing your teeth.  It is cheaper than the sealed battery Sonicaire, and when the battery dies you don't have to wait for it to recharge, just pop in new batteries (I use NiMH rechargeables).  So the downside is that you have to dry the unit carefully after each use.  I still cannot find out how the water is getting inside the unit, but it is irrelevant if you dry it well enough.  Don't bother with trying to seal the unit, it is more trouble than it's worth.  My current unit is a year old and working fine.  BTW, save the battery cap from any old "dead" units.  I dropped my new one and the battery cap broke.  I used the cap from the dead unit (cleaned off the corrosion) and it worked fine...so at least I got some utility out of the dead one...sigh.  Minus one star for stupid design flaw.