the differences are in that all the amp setting in this post comes from different ampifiers
Different amplifier are voice differently, having different speaker configuration(8", 10", 12" etc), different speaker brand, close back, open back and so on.
And if you did try all the setting, it is only with the amp that you using. Imho, there wont be much differences at all, except increased/decreased bass, mids, treble etc...