I do prefer transparent , security and decentraliziation. If and exchange can be Build on the foregoing I think I will seriously like it. The security of the exchange platforms is very important and we can see how much has been lose through hack on exchange in the past because of lack of security.
Money matters, it's our hard earned money so what we wants is the security inside the exchange where we will be exchanging and do our trades,
with continuous updates and progress regarding to security exchange might be appealing to me, together with customer assistance if centralized
exchange.
Protections of assets, making sure that everything is safe against intruders and hackers.
It’s not only bitnex mate, we have quite a number of exchanges that has these facility in place, bitfinex is also good but I recommend binance. They give opportunity to trade in margin and give you an option of placing stop and loss.
The most important thing is for the user of any particular exchange to understand the terrain, check for pros and cons before using an exchange as most of them tells you they offer this service and you get to know they don’t once you register with them or put in your money for trading.