I used one when I had my braces (and frankly I should continue to use it). It is effective for removing plaque and debris and is more effective than floss There are better and worse ways to use it. It should be used gently. Don't aim it so that you end up driving things down into your gums. My model has a setting that allows you to regulate the force of the water from one to ten. To me, that's better than just high and low.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher