Well, in my perspective, these (i only watched 1 so far) dont count as OVA...it's more like soft-H version of the Freezing, with new Vibration chars. Because not only they dont have any stories...it also not too propriate to watch them in public. Overall the art is the same as the original. 4 stars for you who's looking for fan service (5 stars would be full-H for me) 1 star for you who seeks some side stories