Forex trading EAs or robots are made by programmer on the basis of given strategy. And there is no strategy that work in all type of markets. You need to up date your strategy according to the market situation. When you use someone else robot, you are just blindly following someone. Robot is good if you can make it yourself as I do. There is another problem not every broker allows using robot. But I can use my robot with XeroMarkets as they allow robot trading.