One thing that certain on the market price that we cannot perfectly predict the future of the prices. We may get more than 70% win rate with backtesting along with things that already happened (e.g Brexit, crisis in Greece, etc.), but we will never know what kind of big impact that will happen to the market after. In my MT4 platform with FreshForex broker, I prefer full automated trading so that I can see the results of front-testing of the A.I.