I'd recommend the BitShares DEX. It has a bit of a learning curve as it's a decentralized exchange, but it's worth it! With Bitshares you own the keys to your crypto assets, on a centralized exchange like BitFinex you own nothing but an IOU from the exchange.

@tonypeacock made an excellent how-to tutorial the other day for beginners:
https://steemit.com/bitshares/@tonypeacock/bitshares-how-to-tutorial-video-1-setting-up-a-wallet-on-the-bitshares-dex