skinratings

hi I am not new to wincustomize I am just new to forums, I ve been downloading a lot iof skins and I noticed that some skins have low rating even though the design is quite nice and quality is quite good, so I guess the question is how do you rate skins, and how do you decide which skin is high rated and which needs to have low rating? is there like some sorta table you guys look at in making dicissions and rating skins