Well, Okex isn't that "new" exchange, I would say that it is rather old. I don't use this exchange, bacause I've got CoinDeal and I don't plan to change it. Okex sounds okay, but it is not so popular among traders in my opinion. So, I recommend you to choose more reliable exchanges like for example Kraken, KuCoin or as I've said before - CoinDeal. The last one is my favourite because of its security practices and free deposits.