My research is related to integral model of Shimura varieties. I realized there are two approaches building models for varieties of pre-abelian type and abelian type. I want to know what their differences are and how to tell which one I should use in future. So I am looking for some suggestions both from a learning point of view and a "know it so that I can use it in research" point of view, with no disrespect to either mathematicans.