Any exchange has a risk, hackers or fraud can hack. Because our funds are managed by the owners of these exchanges. In order not to worry about your own money, you do not need to keep a lot of money there. Set the maximum protection. At the moment, the confidence of Bittrex, Binance, Kraken. Poloniex confuses me, support reacts to letters once every six months, they often freeze money, and people can not get their tokens
a few months. The limit on withdrawal in dollars, it is not profitable when bitkoyn grows. I think that in the near future, decentralized exchanges will become popular.