Binance and bancor are two reputable exchanges of Cryptos they should ensure that they employs experienced cyber security experts to prevent hackers from gaining access into their system, this give credence and credibility to them and encourages more traders to use their platform and will go a long in trusting their system.
Did Bancor not get hacked recently? I would strike anything from my list that has proven not doing enough security in the past. I trust mainly Binance and Cobinhood now, and Kucoin to some lesser extend, I think these are the safest right now.