This is done very well. She's sexy and provocative, but not in a outright ridiculous way. She's classy sexy, and that's very good. Her shape and hair remind me of Cortana, as if this is what she'd look like if she wasn't digital. And here, she's actually useful. Cyborg body is very well thought out, but just one question: where does the sword go when she's not using it?
This girl's face has a personality to it that doesn't really fit Rei. Her posture gives her an attitude like, "yeah, I'm badass. You know it, and I know you like it." Rei doesn't really have emotions, and when she shows them, she's always timid about it. Asuka is the one who acts like she's all that, even though she isn't at all. If only Rei acted like this...I agree that the blood red eyes would have made this picture even better than it is.
Truth! Rei doesn't flaunt it because she doesn't know she has it! Her half-alien nature makes her cool and since she was quote, unquote "created" she had no past to draw on, Still put her in front of an Angel and she'll go off big time! Asuka is A BITCH!!! period, but her attitude comes from insecurity and a sense of abandonment, but back to your Huntress yeah i'd like to think of her as Rei unleashed if she had red eyes! again great artwork!
Reminds me a bit of Alita/Gally from the manga/anime Battle Angel Alita/GUNNM, which is far from a bad thing. It's actually quite awesome, really. The lines flow quite well and the cybernetic joints do seem to indicate that she isn't entirely flesh and blood, which makes her even more interesting. Wonder what would happen if she went up against the Cyborg Ninja Grey Fox from Metal Gear Solid or Raiden as of Metal Gear Solid 4 or Metal Gear Rising: Revengeance.
I should point out that in order for female armor to be effective, the upper torso should be less "boob" oriented and showcase a more androgynous feel to it, just my two cents on the matter. Regardless, your work is impressive.