Pretty much Tubbers summed up the pros and cons of each system. The easiest path is to choose a point system. Everyone knows its unfair but still agrees to follow it so there is not much discusion.
However, another con I would add to point system is if you fuck it up eventually by having troubles to track points or losing the point count, you'll be sold ^^;
My shell uses point system for instances such as dynamis, limbus, etc and /point system for everything else. Basically because we can not reliably mantain fairly updated points from random stuff where you can't track members all the time.
Anyway, like others said, it won't be fair to everyone, ever. That simply doesn't exist. People have to trust on you, get over it and learn to don't be greedy.
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