BITTREX➡ The crypto trading center with a large number of transactions every day and can exchange all types of coins
POLONIEX➡ is one of the reliable, easy-to-use exchange platforms with many features to create a good trading experience.
BITFINEX➡ has 3 unique features, namely: providing liquidity services, margin trading exchanges, can exchange bitcoin to usd and fiat exchanges.
KRAKEN➡ is also the best crypto platform that can exchange bitcoin to US dollars, Canadian dollars, British pounds, yen and euros, while also having a leveraging and margin trading account feature.
COINBASE➡ the most solid exchange platform that still exists untill now and is the first platform to offer bitcoin purchase features with credit cards.
Coinbase? I think this isnt an online exchange but coinbase is only a wallet .
About the four exchange that you mentioned above , i already heard them but i didnt manage to use them except from the wallet coinbase .
I only use etherdelta and and livecoin.net before to trade my coins and vouchees that i got from this forum but im also looking forward to try other exchange because ed is getting bad day by day and livecoin is already closed .