For me poloniex still better because they have margin trading, i am good at predict up/down trend so i love poloniex.
I concur. There are a lot of tools to use for technical analysis unlike Bittrex. Poloniex has listed decent coins with good volumes so you will have no real problem. Though, nowadays, Bittrex has been strict so you need to verify your account. Bittrex is nice also since there are a lot of coins listed there.