They both approach head drawing in different ways but if I'd have to choose between the two I'd lean towards getting this one. Stan's premium content focuses more on the shading aspects of drawing the head while this course goes over more of Hampton's construction method to developing head drawings.

So much of illustration is developing words and ideas into pictures with intention. Drawing from imagination is a skill that can be developed and improved upon, but the vast majority of professional illustrators are working through a reliable process: research > ideation (thumbnails) > reference > final drawing > final painting. It's reliable and repeatable. I walk through the process in ideacraft, as well as different ideation pipelines to assist in the development of pictures that you want to create. The process works in the following sequence: Observation, documentation, interpretation, imagination, realization. I truly believe these systems can help you. I also worked as a painter for a number of years and relate to what you are saying:)