I've only used this water pik for a few weeks. I can't seem to adjust it so the waterstream is firm but doesn't cause pain. It seems that the water stream is so narrow that I can't get the amount of pressure set as I would wish. The water pik PULSES and that makes it hard to adjust too. I like the knob and on off switch which are easy to maneuver which is important since I have arthritis. The water reservoir is a bit small so you have to get around your whole mouth quickly and then refill it. I Switched from Interplak since that one broke. This is adequate and hopefully will last me a while.
This is the first time I have used a Waterpik and I'm very well satisfied. I have complete dental implants, and the pulsating action of the Waterpik really cleans well.