I use two exchanges i.e. binance and cex.io, i personally love binance for trading. Alot of good coins get registered on binance, its very reliable exchange, easy to use interface, secure and great helpful team.
Binance is fine, of course.
BUT I wouldn't trade in Cex.io now. They were ok a few years ago, but now the userbase and trading volumes are declining daily. So I wouldn't keep any significant amount there.