Review (4/5): It's not like a Water-Pik, if that's what you are after
Bought this for travel use on our trip to South America recently. It worked well and doesn't leak, but it's not the same as a Water-Pik. Instead of the pulsating water action one would expect, it sends out a continuous stream. Because of this, it doesn't clean as thoroughly as a Water-Pik does but it's definitely better than other things if one just wants to do a quick cleaning to dislodge food between the teeth. Reservoir is quite small and only holds enough water for 15-20 seconds of cleaning.
It seems to do good on a battery charge, but it does not have a standard mini/micro USB charging connection, but rather it has a proprietary cannon plug. So, if you misplace the cable that comes with it, you are out of luck. It has its pros and cons but it's not bad for a cheapie Water-Pik knockoff.