Curious as to bipedal proportions, especially, as there seems to be good stylized, even with larger than life heads, eyes, yet they look "good". Is there a chart like there is for proper anatomy for drawing? It'd be great to see a comparison even though I realize there are many forms of stylized. I think that'd make a great article.
Your link to the Substance file on polycount is broken, the correct link is: http://polycount.com/discussion/comment/2294007/#Comment_2294007
Arseniy Korablev has presented a project called Ancient Ark, which showcases the power of Polybrush.
A small animated piece demonstrates the possibilities of modeling in Polybrush. All modeling here is done in Polybrush, animation and rendering in 3ds Max and V-Ray.
Arseniy Korablev has also released v1.7 of the tool, which includes many important internal changes in brush library. Polybrush is now said to work much faster.
You can find more details on the modeling tool here.