Both are great exchanges... And I use the two. Binance app thou is more swift to use.

Kucoin and Binance offers fees of 0.1% per transaction. But I like the fact that as holder of Kucoin tokens, I can receive half of this transaction back through kucoin's unique dividend system.

As for Security, Kucoin and Binance are both very secure if you enable all security features for your account.

Binance Customer service is nothing to be proud of at all. Takes long for them to respond to tickets.
But then, when it comes to the total number of asset pairs offered, Binance is the winner.