I do like it, this should be entered in that contest, but then you would need to do the hair over, because photo shop isn’t allowed I think.
It may sounds off-topic but:
How did you do the hair in Photoshop?
It’s a very good hair.
Very nice work.
some small critiques:
There is something about her pose that looks slightly odd for me. I think is the relation between the hand twist and the overall body twist. Or maybe is only the framing.
Actually the lighting is flat - a typical issue with the AO is that it does not allow color bleeding and correct light bounces.
the face material is great, the helmet is great but both seem not to work together.
The upper part of the helmet is great = the shoulder shows some light issues.
The background might interfer with the shoulder and they are fighting for attention.
However besides that I have to add that this image is still a great piece.
The skin and lips are just great !!!
Dude!! Was this modelled in Blender as well as rendered?
Your op only mentioned that it was rendered in Blender, but I assume you modelled it too?
Amazing work!
Might be a tad overexposed, but the detail is incredible!!!
Setting of SSS and 3D view was showed below.
Picture of hair was combined with Blender image on photoshop, then I painted the details such as high lights and the end of hair with WACOM tablet.
I hope this explanation helps:D.
Attachments
I second the comments about the helmet and face not quite going together. It seems… I don’t know, weird. Uncanny Valley, maybe?
The only other comment I have is the hatch. “Caution: This hatch do not remove”. It’s not exactly, umm, intuitive grammar. 
Internal render!? That’s amazing~!
I can see the skin shade is so perfect~how to do that? You just paint the skin texture using wacam directely or using some photo to adjust the size and color?
And the hair color, how to control them? The first attach pic looks so real~
And 5 stars from me~!
Picture of hair was combined with Blender image on photoshop, then I painted the details such as high lights and the end of hair with WACOM tablet.
Interesting. Very well done.
Oh wow this was done with Blender, awesome! I saw this on the CGsociety, great work
Excellent, I love the face, especially the nose.
i want to be like you! How do you make her face so real?
At first look I couldn’t belive this is BlenderInternal. Amazing skin shader!
And she is surprisingly beautiful girl 
(because many CG Girls are often plastic, lifeless and unpleasant)
Modeling, shading and lighting skills are beyond reproach.
My only complaint (other than the face being at an odd angle) is that the texture of her lips seems too bumpy, but only by a little.
Overall, it’s very impressive! I like the some-what anime-styled face (if only the nose was a bit smaller), and I can’t believe how good that hair looks. Especially from being photoshoped in (but it does not seem to be reflected in the card she’s holding).
Oh, and my favorite is the red haired version. 
Wow… amazing SSS
Wow! I like her “techno Emo” design! I’m joking… really Cool Work Man! 
sweet!..
i like the red one!
WOW ar you like a pixar animator ?? this is the best artwork i ever seen !!!
I try so hard, but I can see any Paris Hilton style droopiness in the eyes. HOW?!?!?!