In terms of performance, the IO Series 9 is unrivaled. It has already earned its five stars in our opinion. If you've been meaning to brush your teeth, the feedback from the handle and app will remind you to do it properly and fully. If you're happy with the state of your teeth and the way you brush them, you'll probably quit the app quickly. As a result, the smart component of this gadget will be useless to the vast majority of people. But that's OK because the IO's major selling point is its screen. It's hilarious, absurd, useful, and useless in roughly equal parts. You're not going to need it in any manner. However, it is possible that you will desire it.