Bought this brand and model because it was only choice on shelf, and it was pricey.. Almost immediately there was and still is a problem that may be a design flaw in the way the water conduit attaches to the tank. The water pulses frequently cut off while the motor is running. It seems that the position of the water conduit is very sensitive for water flow. Therefore the position you have to be in makes it cumbersome and difficult to use. Either that or the unit was 'bad' right out of the box. Either way, not impressive. I usually use interplak--doesn't have thus problem. I was traveling and needed a unit for tooth/gum problem and the travel unit by WP wasn't working that well either.
Like this product very much. This is our second waterpik. If this one last as long I will not be buying another for at least 15 years. The only difference with this one is it is a little noisier than the first one.
I bought this mainly for my grandson after he received a bad report from his last dental cleaning. He had gotten braces about 5 months ago, and had not been cleaning his teeth around the braces very good. This helps him to get the plaque off.