Outstanding. When excessive tartar shows up on an X-Ray it's time for a WaterPik. Flushes out food that brushes can't reach. Ensures food residue between teeth don't become plaque and tartar which can cause pain and eventual gum disease. And you won't have to hear the hygienist and dentist say "looks like pretty good tartar buildup behind that molar."
This is the first water flosser that I've purchased. I've used it daily for approximately 2 months and love it. Love the number of tips. Only con is that it a bit noisy. But I'd recommend it.