Bitfinex is one of the largest exchanges in terms of daily trading volumes and overall recognition. It was founded in 2012 and it is based in Hong Kong. 72 trading pairs are currently available on the platform. The pairs are linked to the four currencies including USD, EUR, BTC and ETH.
Bittrex was founded in 2014 in Seattle, USA. There is also a Bittrex International division, which is based in Europe. The list of coins and pairs is reaching hundreds which is great for many trading opportunities.