Poloniex, at one time, was the best exchange out there. I loved their site, and everything about it. They are in a state where they've completely shut their doors to any new currency (for the better and the worse) and are riding on the reputation and established platform they have, with 4-5 cryptos where they make half of there income from.
Both Polo and Bittrex won't last much longer, the FEDS are up their asses extorting traders information. I woulden't touch either those exchanges, solely because they are based in the U.S.
I completely agree with you here. For a long while I traded exclusively on Poloniex, and this is how they repay me: by refusing to release thousands of dollars worth of coins. I'm afraid to try Bittrex. Guess I'll just stick to my dayjob for now.