I recommend using Bitfinex, best exchange I've found until today! The support is amazing they are available 24/7 and all over the Internet. They have huge verity of coins which are very high quality. They keep on updating the exchange with new interesting coins such as SEER. The UI is pretty clean and deep, you can view charts in quite a few different methods. I love the features of Margin Trading, no exchange has proper margin trading but Bitfinex have implemented it in the best way. They are even working on future of exchanges with Digital Asset Fix Gateway. I am in love with Bitfinex, they have everything I need. They are the best out there!!