My favorite exchange for ERC20 tokens right now is Etherdelta. Some people may find it clunky or slow, but I love decentralized exchanges and I think they are the future. I love being able to keep my orders on the book without exposing myself to third party exchange risk.

I was hurt pretty badly by the Bitfinex hack in 2016 and the BTC-e seizure this year, so I am much more careful now. And since liquidity is not that great on Etherdelta, I often get great sell prices because people are desperate to buy when there are no asks on the book.