KuCoin and Binance are too great exchange site with a high volume everyday but I must prefer to use Binance since Im comfortable with the design and ui of this exchange site it has also an android application that easy to use the withdrawal transaction are good over all Im satisfy to this exchange site.
both are a great exchange. the most important thing is a daily volume that influences market volatility. but i prefer for binance because binance are secure in my opinion. They have a security system built in to check for unnatural movements.