What stands out in this wonderful 3D portrait is the body language of the character (the pose). Her face is caught in the middle of an expression as if she is going to greet someone who has just come to see her. The closed hands in her lap also lend a sense of composure and perhaps a bit of defensiveness. There is a story going on outside the frame of the portrait. This sense of life is what makes Miss Nikol such a masterful composition. Not to mention the fact that the clothing, lighting, rendering and everything else is flawless.
Virtual_world is a top-class artist. You should see more of their work at Renderosity.