Sublime! I love the yin-yang theme between the ladies, but I think my favorite touch (aside from all the thigh-high stockings, ROWR!) is the sort of tattered, worn-out look on the wings of the "Dark" woman. The "Light" woman has wings that are pure and untouched, while the dark side is weary and threadbare with use. It makes me think of...depression.
As anybody who suffers from chronic depression (and not just 'feeling sad', which some wave it away as), a good deal of the time you do your best to show the world a happy face. You could be the life of the party, crack everyone up with jokes, romance someone with a suave demeanor, but inside, you feel torn up, shriveled and blackened. It's the...well, the dark side of the moon.
I doubt this was what you had in mind when you drew it, but the beauty of art is finding your own meaning within the beauty that other people create. And this is definitely beautiful. Even the sadness it makes me feel is beautiful, in its own way. Thank you.