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

GBX is developing a token sale platform and digital asset exchange that is designed to make traditional investors more comfortable with investing in cryptocurrencies. The Gibraltar Blockchain Exchange (GBX) is a subsidiary of the Gibraltar Stock Exchange (GSX). They hope to use their position as a regulated European exchange in Gibraltar to position themselves as a reputable option for investing in digital assets. GBX issued an Ethereum-based token called Rock (RKT).