If you are not exhausted by the discussion or you want a video summary, I found this video to be entertaining and educational: https://www.youtube.com/watch?v=RCbzM_Ds3o8
One of the key points is that it has been proven you can’t have a voting system that doesn’t have at least one of these properties:
- The system is dictatorial
- The system is rigged against one of the candidates
- The system is not strategy-proof
Since the first two properties are highly-undesirable, we are left to choose between systems that minimize the amount of strategy (i.e. minimize insincere voting). The 3-2-1 system has been specifically designed to minimize strategic voting and according to vote simulations does a good job at it.