I got out of Poloniex right after they pull out the troll box. That was a signal for me. I see many ppl on troll box messaging tickets that they had issue withdraw. But all the exchanges....yes...including Bittrex will have issues. My friend got his account hijack on Bittrex. I myself added some ETH onto Brittex but I did not show up. Brittrex never resolve the issue. I lost my funds.