I think something important to note is that NEVER keep a big amount on any exchange.
I would recommend bitstamp in normal days , but as of now, my account is locked from withdrawing btc for the last 4 days and no reply from the support yet.
I don't have a big amount of crypto stored there, but there is a big bank transfer going to them from 7 days and they did not even confirmed receiving it yet which is so worrying...
Point is NEVER trust an exchange with alot of money as point of crypto currencies is having your money under your control, and not third party's control
RE: 8 Digital Currency Exchanges with USD to Bitcoin!