It's been about more than a year since I have started my journey with Kingfin. I should say that I am quite surprised how fast payouts and how transaprent is the dashboard. 
I guess these are the main criteria if you want to be an affiliate and want to get profits. 
The Olymptrade is the broker with a big name, so, if you have set up channels where to attract traffic, then you almost have the job done. The main is to watch for those people you attract, as they have to trade while you generate profits from their activity. The concept is clear and simple, I like Kingfin for this.