Classy, very classy.
My one complaint is that the highlights may be a little too opaque, like a good blurr tool could make it seem more natural...eh, just my opinion, still good either way.

You should really color in the things you draw more often.

An interesting character design to say the least. The facial expression and pose are very expressive. I particularly like the look in her eyes coupled with her smile, it gives her an air of mischief.

The hair and tail are wonderfully done. You convey motion well. From my side of the screen its all too easy to imagine the flowing of the hair and tail and the swaying of her body to accompany it.

The only problems I can see are some of the shading and highlights on the hair. The shading between her ears is well done. It's smooth and runs with the flow of the hair. The shading on the main body of the tail behind the arm is where it starts to look almost blotchy. The highlights on the tail in the same area and highlight on the lowest left part of her hair as well as the upper right hand highlight next to her cheek appear more drawn for lack of a better term. Like that one area of shading I can see where the tooling begins and ends. It just doesn't have the same flow of light and shadow in those areas.

The highlights on the metal portions look wonderful though.

Over all I like this picture. I like the character design and frankly she's got life in this depiction.

Well done.