I thought that the only good thing is the primary exchange site which gives the more guarantee about the service. The big exchange site provides an easy way for you to liquidity your amount. As far as i know, it seems to become the best choice for you but remember to avoid those exchange sites which had so many problems.  

Binance, okex and kucoin look become the best choice for you to use it as the best place to buy and sell altcoin.