I dont follow signals anymore, but when i did, I would try to go with ones over a year trading history. You tend to see a lot of people "cluster" for signals that are only 2-3 months old and take high risk (I been one of these people before). I am yet to have "any" survive past 4 or 5 months. If you dont believe me, just bookmark some of the ones you are interested in........and then just watch them. 80% of them wont be there 3 months from now. 20% will survive, with 10% having a drawdown that exceeds 70%..........or will have lower draw-down, but see where they made an emergency deposit so the drawdown will not look bad. The remaining are stable but grow very slowly, some being so slow that you have to have a large balance so bigger trades can be placed (otherwise you will profit just as much as the monthly fee itself).
The good news is when you do this long enough, you start to create your own strategies, so dont be afraid to fail or purchase busted EA's. It all teaches you things if you have the patience to learn it. After a while you will develop an eye for what strategies are stable and which ones will blow soon. The best indicator i've noticed is the length the signal has been open, and the broker (only go with the major brokers types.) I personally think that sometimes some brokers post their own signals to make it seem through live account with long trading history. But when you google the broker, you hardly find any good info on them.