EtherMium is the most advanced decentralized Ethereum token exchange. Here are the advantages compared to other decentralized exchanges.
EtherDelta was the first major decentralized exchange built on Ethereum. While providing the security of a decentralized exchange, EtherDelta is a very complicated to use while robust exchange.
Advantage of EtherDelta is that the user is communicating directly with the smart contract when performing trades and withdrawals without having a server to intermediate this communication. However EtherDelta is still using its servers to record and post orders, so if the server goes down, there is little you can do except withdrawing your funds.
The big disadvantage of EtherDelta is that you can never know wever your trade is executed until it is confirmed by the blockchain and there are plenty of situations when two or more people are trying to trade the same order and you may not get the order because someone else's transaction was confirmed first, leaving you paying the transactions fees for a failed transaction.
Another disadvantage of EtherDelta is the fact that you have to trade a specific order, you cannot just specify a quantity and have the exchange perform the trade against several orders. This means that if you wish to trade a large quantity you have to manually trade orders one by one. Combined with the possibility of competing for the same orders with other traders, this process can be rather lengthy and frustrating resulting in many failed transactions with lost fees.
IDEX marks a step forward in the evolution of decentralized exchanges. IDEX sends the trades through its servers, meaning that you do not have to compete for the same order with other traders.
The disadvantage of IDEX is that you have to trade specific orders. Their frontend helps you buy selecting the best available orders, however you still have to sign for each order, meaning that if you are placing a large trade you have to press the sign button multiple times on your MetaMask. Combined with the sometimes slow MetaMask, this process can take a long time and be frustrating. EtherMium offers a more advanced order matching mechanism on its smart contract, that allows users to sign the order only ones, our servers then match the users order with the best available orders on the order book and sends them to the contract.
We have spent a significant amount of time looking at all types of exchanges available on the market today and made sure to take the best parts from all of them and significantly improving on them. Overall we believe we have created a balanced product that behaves exactly like a centralized exchange in terms of performance while providing the level of security only available on decentralized exchanges.