Coinbase Pro, formerly known as GDAX, is the best exchange for beginners. The UI is easy to navigate and user-friendly. It is also fully integrated with Coinbase which is still the easiest way to buy the big 3 and enter the crypto space. It is interesting that you can use Coinbase Pro to buy Bitcoin, Ethereum, etc.. for a smaller fee than on Coinbase. They are cutting into their own profits. My main gripe with Coinbase Pro was the verification process. I took a bunch of selfies and photos of my ID yet it still took forever for the automated process to accept my identification. I wish the AI behind that worked better. I also wish there were more cryptos available in fiat pairs on Coinbase Pro. That would help newcomers invest in more varied altcoins and could possibly help the markets decouple from Bitcoin.
If you have a Coinbase account, then you have a GDAX account. Just sign in and trade your Coinbase coins for free on GDAX. They still have issues with slowing down during heavy traffic, like a lot of exchanges. Keep an eye on Coinbase and GDAX because they will soon be adding new coins to buy/trade.
When it comes to price of fees and exchange to bank account transfer gdax can’t be touched. Gdax’ fees are super low, they transfer funds to your bank account extremely fast. I have nothing bad to say about gdax. In my opinion this is setting the standard for how it should be done.