What is missing in this image that stops it from looking like a photograph?
The hair seems to have sampling noise or aliasing in it. This might be poor jpeg compression but it does not look like it.
I've never seen hair part that way (could just be me).
The neck looks a little too regular (I'm no modeler though).
The skin's subsurface scattering falls a bit short. Perhaps it's not that but there is something slightly off about the skin.
The shirt has a slight plastic feel to it.


Most of this is entirely subjective of course. I think it's fairly good but falls short of the state of the art in many areas.