I know this thread is old... I just want to update just a little... https://kraken.com is up since 2013, and it has been some connectivity problem during 2017 due high traffic. Nevertheless, they have made a good job on January 2018 and now looks good... I do hope it will continue in this way. It is a nice place to trade (it works with FIAT too), on the other hand, they don't have advanced trading orders or they have them disabled as stop-loss, THAT SUCKS!!! FIX IT!!! PLZ!!!.

My "only crypto" favorite exchange is https://binance.com it has a great performance.