I made a distinction based on survivability - whether imprisoned or whipped and sent back into the Shadows, Moghedien has a better record than Balthamel, Aginor, Asmodean and some of the stronger Forsaken. Sammael ended up getting caught in an alliance he didn't want, and despite his maneuvering, he ended up getting hunted down after a longer chase than the others. While his record speaks much for his tenacity, I don't think being run haggard by Rand and Co. says as much about his survivability as his ability to run a defensive battle.

But it is generally the case that the Forsaken are so busy trying to destroy the protagonists rather than outright kill them, that they end up getting killed by brute force as discussed in other posts above.