In my opinion of course Binance. Right now one of the biggest exchange in crypto industry. Many people trade there crypto satisfyingly. Exchange age not too much but in short time they showed that what are they capable with. Other hand Kucoin also a new exchange like Binance but they didn't stand like Binance. But trader also like the strategy they way kucoin run their exchange. They have some cool stuff also like Binance. But first choice is Binance.