UNUS SED LEO is an initiative started by Bitfinex that is focused on increasing the exchange's transparency. UNUS SED LEO means "one, but it's a lion" in Latin. The iniatative was created to increase the transparency of the exchange's finances, following a controversy related to the allocation of reserves from the stablecoin Tether, that was created by the same parent company as the Bitfinex exchange, iFinex. It is built around a token burning redemption mechanism which is tied to the parent company's revenues. Their dashboard provides insights into the fees that are collected, and the LEO tokens that are burned.

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

Bithumb is the biggest Korean crypto exchange. It is a top 30 exchange by trading volume and it is one of the most significant blockchain companies in South Korea. In June, 2018, Bithumb was hacked and around $870,000 in bitcoin were stolen from customers.
Trading Fee: 0.15%
Withdrawal Fee: 0.001 BTC
Number of Tokens/Coins: 32