As much as one-API-to-rule-them-all just doesn't work, introducing multiple Python-based APIs for ArcGIS raises some questions. One question that has been nagging me is, "what is the preferred, or better yet optimal, way of transferring geometry objects and record/feature sets between ArcPy and ArcGIS API for Python?" For me, dumping the data to intermediate file formats isn't efficient, so I am not looking for that to be the answer.