At first, I was very dissatisfied as it makes an extreme amount of noise and my whole head shakes when I use it, but after using it a few times, I quickly got used to it. My teeth have never been this clean before, and I've noticed a big difference after using it for just 2 weeks. It doesn't need to be charged often. The app function and AI function are terrible, so if you want to buy it because of that, I would choose another one. The AI function doesn't work at all and is completely off track. It quickly gets gross and moldy inside the brush head if you don't clean it well every day. All in all, the features are not top-notch, but it gives me super clean teeth without irritation of the gums.