Is okcoin and okex same exchange or different exchanges?
What about okcoin exchange ? did you use it before ?
OKcoin is the fiat version of OKex.
While OKex is one of the big names in the exchange markets, fiat operation requires a different licensing, AML and KYC. I guess this is the reason to create another company with US-based licensing, but allowing you to use the same credentials.
I'm using OKex on a daily basis for Futures trading/arbitraging, but if you need a fiat operations, my advice is to choose some of the bigger names like Kraken. Kraken have ultra-cheap and fast SEPA withdraws and 20x higher volume.