Replaced an older model so tips are interchangeable. Multiple pressure settings. Improved water on/off switch design. This unit seems to go thru more water than the older model but that is no big deal.
It has performed well, for what I use it for; To clear out food particles at /just inside of my gum line. I gave it 4 stars, because it is a bit noisy. But does not 'creep' across the sink countertop. I have only used the one attachment for doing gumlines, and not any of the other ones that do come with it.
This product is really quite amazing and useful. I previously thought that string flossing was the best way to go, but using the Waterpik for flossing -- when combined with string flossing -- provides superior cleaning to the tooth and gums. I'm very happy with this product and glad that it was recommended to me.