OKEX hasn’t been the target of major hacks yet. While this brings some assurance, in terms of security, it does not guarantee this will not happen in the future.This is a lot better than the average of around 0.20-0.25%, offered by most other exchanges. On the other hand, the forex brokers, who provide Bitcoin trading include their costs only in the spread. While it is a bit hard to compare spreads and commissions based on size, you can check out this post to get a better picture.