Binance for sure. Nice UI, and trading fee is very low, customer service are great. It is the best exchange I have used. My only complain is that for each trading, the trading value need has to be at least 0.001 BTC. I have some coins that have shrinked a lot in value, so I cant sell them.
The only reason I use Kucoin is because I wanted to purchase some NANO at that time. Oh well, what should I say? The website is slow as hell. I thought buying 1KCS is more than enough for reducing the trading fee in half, just like in Binance. But no, it requires a lot more. And a few weeks later, Kucoin suddenly announced that it will NOT provide service to Chinese customers. No prior notice or grace period. When I tried to access the website through VPN, it remembered my previous browsing history as a Chinese IP and denied my access. So I switched to another browser, it worked but extremely slow. If I disconnected my VPN and leave the Kucoin window open, the damn website will remember the Chinese IP again, and I would be denied next time. My brother had a lot coins in there. So it took us quite some time to transfer the majority of his asset out to another exchange. In no way I would say Kucoin is on the same level as Binance.
If you want smooth experience , speedy withdrawal and nice customer service, go to Binance. If you hate someone, tell him to use Kucoin.