It's good to see more people are choosing to use decentralized exchange. I have also been using decentralized exchanges for a while and can share three of them based on my personal experience.

1.EtherDelta or ForkDelta: I think they are the oldest. People sell their altcoins received from airdrops here, because there are so many pairs to trade. lol

2.IDEX: Probably now the most popular one. The order matching mechanism is improved which is the pain point of many other decentralized exchanges. While the trading fees are sometimes more expensive.

3.JOYSO: A newcomer. It also uses improved order matching mechanism and the trading fees are lower. However, many pairs still don't have volume because there aren't many users.