EA are there to cheat people's money mainly, its all about marketing the product, if you cannot trade as fast as a robot like a scalper. scalper is also high frequency trading means higher change to lose money as well when you keep changing side. then its time to learn price action on daily chart.
Price action on daily chart often may have up to 75% hit rates of success.
Please learn that CHARTS on the backtest are total different from LIVE! results on backtest is of no use! Please learn that! if you want to try a ea, please do it live. and see its reaction, you also need to control the EA trading hours, especially during heavily volatility.
I did more than 50 Ea tests, and none can do well under LIVE, not even MDP can do well either, hitting stop loss non-stops. So, its very determined by the speed, broker and etc, as well as the live rate, requotes and slippage.
So some EA may work for someone, while suck on others.
I personally don't recommend buying ea online, since its all marketing a product and cheating money. EA must be customized, optimized.