>>399
When you're transitioning between planes like that, I would have it slightly darker at the terminator/where the light side ends, just as an effect to help the form read more.
This is the 4-value simplification thing, right? It can be tough to know which value to choose. But I think it's a good idea to choose what will help the lighting read better. For example, in the first one, have the hair on the top of the head be the 3 value instead of the 4 value, so that it be more understandable that the hair below is in shadow.
overall I like the eyes in the second one way better. The gradation in the eyes you added in the first one i don't think really helps.
In the second one, as I said I really think the eyes are well done. The lips may have been better with a darker value, though. I do think you're overdoing it with the generic highlights on the chin and the cheek. The forms and surface are different there than the nose, highlights/specular reflections happen a lot differently there if at all. Though overall a solid simplification in the second one; another thing you could have done is use the 4 value for the cast shadow or occlusion shadow under the chin, but I think it works the way you have it as well.