This fifth book in the Boogiepop franchise is definitely the most ambitious to date. I really feel like if everything had come together it could have been Kadono's magnum opus and taken the series to a whole new level, but instead it faltered every so slightly and takes its place as the fourth best Boogiepop book to date. That's not to say that this book isn't good, because it is, it's just that isn't as good as the opening trilogy of the series.
The strongest defining attribute of the Boogiepop novels, in my opinion, is the interlocking stories from multiple perspectives. It really makes it stand out from the crowd. But in this book it is actually to the story's detriment. Perspectives change far too frequently in this volume and make the beginning of the story very jarring. It also seems to allow for slightly less character development than needed. Although, I do feel like this issue was fixed by the end of the story, but by then it was too late to turn this into a classic.
My biggest complaint of the last novel (Boogiepop Overdrive: Pandora) was that it didn't really feel like a Boogiepop novel and thankfully that issue has now been resolved. This outing really does feel like a full-fledged member of the Boogie-Verse (sorry). Sure there are new characters, but lots of the franchise's main players return in prominent parts. Also, Boogiepop His/Her self does actually interact with the cast this time round which makes a real difference.
All in all, this is not a classic, just another solid Boogiepop story. But in my eyes that's all I really need to be happy. By now you know if you like the series or not, so I think in many respects that one statement tells you all you need to know.