I have been using CEX.io for over a month now.

My verification (at all levels) was super smooth - done and dusted in a matter of minutes. No trouble depositing fiat  currencies [I used an international credit card to deposit USD/EUR/GBP] or cryptocurrency, and none while withdrawing BTC/ETH into my personal Wallet [I use Exodus] either.

I am yet to attempt withdrawing cash back to my bank or card, though.

That said, their email support can be a pain. Take an eternity to reply and, sometimes, don't bother! Their Twitter account, however, has replied to my tweets promptly.

All in all, seems fine - serves my purpose. I needed an exchange that allowed funds deposit via credit/debit - unlike Kraken, Poloniex, BitFinex, etc.