What are the best decentralised exchanges out there, and why are they good?
There is only one that I know about - etherdelta.com. It is good because of trading directly to/from your wallet to another user's wallet. There is no middleman who can be unfair.
For me the best decentralized exchange is hitsbtc and etherdelta because they are easily to use and low market caps in terms of trading or exchanging market value.