I'm impressed. My own experiment with facial anatomy didn't go quite so well.
In my opinion it looks a little too gritty, though you fixed that a bit in your latest version.
I really like how you used dithering on the hair to give it some texture, it works really well.
It looks slightly over-detailed, causing him to look sort of old.
He lacks expression of any kind, which is kind of creepy.
EDIT:
Also, the ears seem a bit low.