Exchanges are always subject to hacking which many believe that the owners who are behind and just made up the hacking incident. So just keep it on your wallet because the only person you can trust is yourself.
I do not really believe in a third party, because they are also human beings who have a greedy nature, whenever they can do fraud or even a scam. I'm not very recommend to keep all your assets in exchange, as many users do that, save it just as necessary for trading, the rest save on a desktop wallet or wallet without a third party, it will be much safer..