> simple question : have you encountered an anti-cheat mechanism that works to stop cheaters?

I find them to be rare, but I consider the existence of both cheating and anti-cheat software to be a symptom of a bigger problem: shitty games and shitty game mechanics.

If cheats maximize enjoyment for the cheater playing your game, your game sucks and you should focus on retooling the game to deliver that experience without third party tools.