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%

Poloniex is an established crypto to crypto exchange that is based in the United States. It offers a large selection of tokens to trade and has high liquidity. Poloniex was hacked in 2014, and lost more than 12% of their bitcoin supply. They have improved their security protocols since then. In February, 2018 Poloniex was acquired by Circle, one of the largest crypto payment providers.

Trading Fee: 0%-0.1% Maker and 0%-0.2% Taker
Deposit Fee: Varying Depending on blockchain fees
Withdrawal Fee: Varying Depending on blockchain fees
Number of Tokens/Coins: 97

Bancor is a decentralized exchange protocol that is designed to increase liquidity for Ethereum and EOS tokens. The company has been at the center of the debate about Decentralized vs Centralized Exchanges, as well as the overall need of institutions to serve as a hub for decentralized networks. Their protocol, and exchange, enable any token to hold one or other additional tokens in reserve. Bancor allows conversions between tokens on their decentralized exchange with smart tokens that increase liquidity, and establish market prices for smaller tokens. Specifically, for those that do not have large trading volumes. Bancor tokens facilitate the exchange and act as a connective tissue, and have a centralizing effect on the exchange.