The Federal government warns there are a lot of Forex frauds out there, and these Forex robots appear to be one type of these scams. If these robots really worked, there would be scads of articles about them in the Wall Street Journal and other financial publications talking about them. When I do a web search, I can not find a single reputable news article encouraging the use of Forex robots. The link below is a Federal website warning you about Forex fraud.
There are a lot of people on the Internet claiming they have done very well using Forex robots. These appear to be of two types. One is the outright liars. You might meet a person called "Zboy227" who says "I made a lot of money using ScamRobot2000, go to their website at ScamRobot .com/Zboy227." The "/Zboy227" tells the website that Zboy227 has referred you. If you buy the product, Zboy227 gets a commission. He is only lying to you to get a commission.
There is a lot of luck in Forex. Sometimes you will run into people on the web who have tried a robot for a few days and have had some beginner's luck with it. They start bragging about how well they have done. Later, they start to lose money, but they rarely get back on the web and talk about how much money they lost. People like to brag about their successes, but rarely talk about their losses. The result is that much of the feedback about these Forex robots is positive.
I may point out that websites that sell Forex robots admit there are a lot of scams out there. Of course they claim the other guy's robot is a scam, but their robot works. If you do a web search on the words "forex robot" and "scam" you will find a lot of sites saying their competitors are scams.
I will admit I have not personally tested every robot out there, and I can not prove they are all scams. But I would be very hesitant to spend a lot of money on a robot without clear proof it really works.