Hope those closures of the mentioned exchanges didn't result in losing your coins 
Otherwise when it comes to the best exchange, it depends on your jurisdiction ad this can't be generalized , and if you are interested in other services the platform offers such as p2p trading this will have to be considered when finding what works for you!
Personally I use Binance, poloniex, kucoin, gateio and a combination of decentralized exchanges depending on where I can find the best price of a coin am interested in...
I have the same way with your without priority with one exchange only and combination for all exchange regarding my habit as arbitrage trading looking the opportunity exchange has bigger transaction volume of my coins arbitrage. Otherwise when it comes to the best exchange, it depends on your jurisdiction ad this can't be generalized , and if you are interested in other services the platform offers such as p2p trading this will have to be considered when finding what works for you!
Personally I use Binance, poloniex, kucoin, gateio and a combination of decentralized exchanges depending on where I can find the best price of a coin am interested in...
Recently I used all exchange not only with top exchange but also not popular exchange such as LBank behind many potential coins for arbitrage by purchasing at dapp exchange and sell it on LBank market.
But I ware from one exchange Hitbtc after my account suddenly reset by them and loss access from 2FA, I am lucky not hold much assets there because that market not recommended for holding long term.
Coinbase recently suspended in my country Indonesian and we can't access any more but get opportunity giving by the exchange withdrawing all access before access locking permanently.