I used Bittrex for trading, it's much easier and convenient to use.
I used computer and smartphone
Bittrex is good on smartphone but not worked with poloniex. Poloniex only can be worked on Desktop, Smartphone will miss some important display that you need when you want to exchange from some coin to other coins. So if you use desktop any exchangers are ok but if you use mobile, don't go to poloniex.com