Finally I finished. After a crash on my HD :(. I hope you like it.
Alternative rendering. For fun 
Not bad.
Her hair looks like a cap. Also, you need to add more details to the clothing (textures).
You need a proper background (environment)
That’s all I can see 
I really like the retro “vibe” with this one, if I understand what you are trying to do
I think this is great work, I like the red and black one most of all.
Also I think you have done a wonderful job with the hair.
Nice work. I like the pop art style.
Isn’t that Rihanna? Nice render, btw.
-Reyn
Turned out great man, the rendering style is interesting but I’m not so sure it does the best job of presenting the model in a ‘realistic as possible’ way. Those eyes are remarkable!
Thx. Yes, but I have no time for this. Im on CGtalk challenge :).
Another render:
