I prefer to use Bittrex over any other exchange website. I used to love using Poloniex before. But during the times when there were a lot of glitches over Poloniex, I somehow stayed away from it for some time. There were a lot of maintenance and freezing of withdrawals. These were the reasons why I shifted to Bittrex. The platform is pretty smooth and a lot of coins are also available for trading. The volume is pretty large as well.