Kraken is a US-based cryptocurrency exchange and one of the largest bitcoin exchanges in terms of volume and liquidity.
It provides Bitcoin pricing to the Bloomberg Terminal and has considerable influence on the overall crypto market. Kraken offers a number fiat funding and transfer options.
There are 18 BTC pairs and 16 USD pair to trade
Fees vary depending on the volume - for main trading pairs this is between 0.1-0.35% - however for other less common crypto pairs the range can be as low as 0.05% or as high as 0.75%. There are also 0% fees for some trades.
Withdrawals and deposits are variable depending on the method - although in general all fees are 0.19% with a $20 minimum.

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%

OKEx is a relatively new exchange that allows cryptocurrency investors to trade a wide variety of fiat and crytpo pairs. Although it is based in China, and caters to the Chinese market, it has a platform that is easy to use in all languages, and has quickly become one of the largest exchanges, by volume, in the world. The highly secure platform provides high liquidity, and has a number of other advantages.
OKEx has a user friendly interface that can be understood by all traders, regardless of their experience. Their platform is a good option for new crypto users because it supports trading of one of the widest varieties of different cryptocurrencies. It is also a good option for professional investors and day traders. They offer high trading limits, future contracts, and a number of other trading tools, including a block explorer.
Withdrawal Fee: 0.1% with a minimum of $15
Trading Fee: 0.2%