I like those exchanges where there are good trading volumes. This is Binance, Bittrex. Lately I like Kucoin. But, I'm really looking forward to decentralized exchanges becoming very popular. I like to trade on the Bancor platform.
For me, there is no problem whether I will be using more exchanges, my main concern is the transaction and withdrawal fees. Also if I heard some bad things about the particular exchange I will avoid to use it.