I tried switching to the WP-450 after many years of using a different device that mixes water and air. I found the WaterPik cleans quite well, but not dramatically better. And the water-only method is just too messy for me to use every day.
I bought this one because my old Waterpik was a couple years old. This one is even better - more improvements. Easy to use. Easy to fill and empty. Variable speed.