@Ether Delta
I agree that Ether Delta (and exchanges like it) are probably some of the best DEX iimplementations thus far because they do not use IOUs or derivatives. However, seeing as though you can only trade ERC20 tokens (which are effectively all very risky and volatile investments) they are still not ideal.
I am still awaiting a more optimal DEX that can exchange tokens between different blockchain without IOUs or derivatives.
I feel etherdelta could be way better if they make some improvements to their interface and the mechanism they use because it's very hard to perform simple actions and it's not user friendly. I get some people already use it with their eyes closed but something that is suposed to receive all kinds of public needs to be more easy and simple to use in my opinion.