Tamito Kajiyama is the developer who has worked on the integration of Freestyle into Blender for the longest period of time. Since 2009 he is the maintainer of the project. In this interview, he talks about the history and hurdles of the Freestyle integration development and how motivating it is to have active users in early stages of development.
Sean Kennedy is a compositing artist who has been working for the notable studio R&H until it went bankrupt (and got a special effects oscar). In his work he had used Blender every now and then to polish his shots. BlenderDiplom talked to him at last year's Blender Conference.