I like the first one too. I would probably try to avoid making the shadows grey. Also add some highlights on the hair. Also some variation of colors for the skin like a subtle and lightly desaturated green for areas where the veins are and subtle and lightly desaturated orange for areas like the tip of the nose and cheeks and the edge of the ears.
As for the second one, I think it lacks proper shadows and highlights that would help to make the painting come out.
I am sure that if you play with shadows and subtle highlights for both of them, you will get decent results.
But overall the first one seems to be promising.
Hope this helps.