I recently purchased a WP-100 to replace my 30+ year old Waterpik. The new unit is much quieter than the old unit, but seems to clean more effectively. My only complaint is that the WP-100 does not hold as much water as my older unit. I find myself needing to add some water to finish the job.
It is like the refreshing, clean, healthy feeling that I used to get with the old-fashioned cleaning at the dentist office. I use it several times a day.
Just bought this replacing old one that leaked. Waterpik does an excellent job, however, it is noisier than my old one. Have to put a wash cloth under it to absorb some of the noise!
I purchased the WP-100 to replace an older model. The new WP is powerful that I only use a setting of 2 to get results to remove all debris between my teeth and under a bridge.