So the unit works excellent. I gave it 4 stars because it is a little hard to handle. As far as operation goes, it is excellent. It you have room on your counter, I would go with the smaller hand unit and tank on the counter. This unit is a big (hand unit) because it also holds the water. Other than that it operates excellent.
This is a great Waterpik except for one feature. It is rather large for smaller hands. I bought it for myself to use instead of the older one I have with basin for water. However, I gave it to my husband because his hands are larger. He loves it.