When talking about the best available exchange in the market currently, the only one that ring a bell in my head is Binance amd i believe a lot of forum members would agree too. Binance is termed the number exchange because it seems to have almost every features needed by traders and it provide the best of services, reduced fee and has almost the highest volume and liquidity which makes it perfectly suitable for day trading
Binance has an easy-to-see interface and has many tools for you to analyze so this is the best exchange you can trust when trading. I have been using this exchange for 3 years now and have never been disappointed so you don't need to worry about liquidity or security because Binance is the best. However, the coins here are still risky if you do not study carefully so the risk of losing money is still very high.