BitFinex is a bitcoin to fiat exchange, a margin trading exchange, and a liquidity provider. The platform offers a number of features that expand the financial positions you can take - for example the ability to short Bitcoin via margin trading.
The exchange also offers a set of other cryptos apart from bitcoin such as Litecoin and Ethereum.
Deposits and withdrawals take place via the standard bank transfer means with fees of 0.1% and a minimum of $20. Bitcoin and Litecoin are free.
BitFinex takes security seriously and have moved from a hot wallet cold wallet set up to segregating customer funds where each user has access to their own wallet which they can review on the blockchain.
Bitfinex was hacked on 03 August 2016 and around 120,000 BTC were stolen.
Fee of 0.1% for most trades

Huobi is one of the world's leading trading platform, committed to providing investors with a professional, safe and honest transaction services. The Exchange charges no deposit fees but does have an exit fee of between 1% and 2%. It was originally based in China, but moved its' headquarters to Singapore, and also has offices in Hong Kong, Korea, Japan and the United States.
Huobi has raised capital from investors including Dai Zhikang, Sequoia Capital and Zhen Fund. Huobi is a major player in the Chinese blockchain scene. It runs a mining pool, (Huobi Pool) incubator, (Huobi Labs) and a research institution. (Huobi Academy of Blockchain Applications)
Trading fee of 0.2%

Cobinhood is a cryptocurrency exchange with no trading fees. Users can trade most of the major pairs, and a variety of other currencies. Cobinhood offers both both a centralized and a decentralized trading platform. In addition to their cryptocurrency exchange, Cobinhood also operates an ICO underwriting service, and they are releasing Zeux, which will be a crypto mobile payment and investment app.
The network is powered by the COB token.