Ethfinex is a decentralized cryptocurrency exchange that runs on the Ethereum blockchain. It is owned and maintained by the same company as the Bitfinex exchange, and your equity and other account information can be shared between those two if you choose so.
Ethfinex does not have a fee schedule, unlike Bitfinex, but traders can earn Nectar tokens (ERC20) for market-making. In other words, Ethfinex distributes a rebate for limit orders in the form of the Nectar token. The token can be traded for ETH, other crypto or fiat.
Users get to vote which new ETH tokens they want to get listed on the exchange. The EthFinex community is also building knowledge base, blog about decentralized exchanges and an informative weekly newsletter.
The interface of Ethfinex is pretty much the same as the interface of Bitfinex, embedded charts are also provided by TradingView just like on Bitfinex.
Bitfinex is a BVI-based exchange infamous for being hacked in August 2016. Despite the hack it still has a wide user base thanks to its superior trading interface.
Bitfinex offers a wide range of markets denominated in BTC, ETH, USD and EUR. They allow Tether withdrawals but the merkets on Bitfinex trade against USD, not Tether.
Since January 1st 2018, there is a minimum equity requirement for Bitfinex - to activate new accounts for trading, users have to deposit at least 10k USD to the exchange.
The exchange is available worldwide. There is limitation on margin trade for Americans - however the exchange is still operational from American IP address. New users on US IP just have to state they are not American residents.
No verification is needed other than for fiat withdrawal.
There is an 10% fee discount for users who sign up with a referral code.