Mercatox is a good exchanger .I have traded there few times.But it is not a great exchanger.They have a few times maintenance problem and some problems in voting system.But their low transaction fee and speedy transaction is the best feature.
I think that its services are not available in my country. I always use Okpay for my transactions. It is also very reliable and trustable. The transaction fee is also reasonable and its services are also good. Different people use different exchanges for their transactions. Binance is the leading exchange in the world and almost the whole world is using Binance.