I've been very pleased with the WaterPik WP-580. It's easy to use and it does a great job with little effort. I was concerned with the amount of water in the tank, but found it only took me a few seconds to refill and start again if I felt I needed more time. The design is so much better for ease of use and it's much easier to NOT change the setting mid-use. The charging seemed to last for weeks...I was amazed when the blue light finally started flashing telling me it was time to recharge the device. You won't be disappointed with this product!