All EAs differ from each other by trading type (trend-following, scalping, breakout, etc.) and by price (there are even free EAs, but they are practically useless). Choose an Expert Advisor that "specialized" On a trading type that you are familiar with, so that you can evaluate its workability. Many developers offer test periods - for example, a month of free use of the Expert Advisor. This is a very useful experience, be sure to test the robot before buying, if possible. Pay attention to the reviews. Search for the opinion of experienced traders, they are more reasonable. There are public monitoring services for Expert Advisors now. They are very useful portals where you can evaluate the performance of a robot in real time.