Field API

Here I am building out a content type for a new project again. I've got to decide whether to use a Option List field or a Taxonomy field. It's an easy choice right? Right? Once you think far enough down a site roadmap, you'll discover it rarely becomes a simple answer. I've read many articles on the subject and nothing I've found seems to cover all details. That being said, if you find any details or related links I've missed be sure to let me know in the comments.