>GOD tier shinies:
change a defining feature to a striking different color (Ponyta, Voltorb, Shuckle, etc)
>great shinies:
change the whole color to a pleasant/different tone that makes them stand out (Vaporeon, Magikarp, Rayquaza)
>ok shinies:
change minimal features to a different color (Umbreon, etc)
>bad shinies:
ran the Pokemon through a saturation filter and nothing more (most of the shinies)
>dogshit shinies:
give them a terrible color scheme (Espeon, etc)
