I recommend Aquapick.

You absolutely have to buy this. My teeth rot easily, so I used to be a flossing enthusiast. Even so, I still ended up at the dentist regularly. But I was truly surprised after starting to use the Aquapik. It came out with a lot of food residue that even floss couldn't remove. So these days, I manage my oral hygiene with a triple routine: brushing, then using the Aquapik, and flossing. Oh, and you know it has to be cordless, right? Between the Waterpik and the Aquapik, I chose the Aquapik because I liked the design.