The arcs of Owarimonogatari gave a little bit of insight into Araragi as a person, and while it wasn't anything too remarkable or crazy, it was still a much needed insight into his character. It also reveals the other side of the events of some of the arcs in Monogatari Series: Second Season, although it hasn't fully reached a conclusion on that front. It has the same great style and sound of something from the series, so no problems there.
Overall I think this is a pretty good prelude to whatever is waiting for me in the second season.
