The Bone Clocks: Or the long weird life of Holly Sykes & friends

First and foremost many thanks to Goodreads and Random House for providing me with a review copy of this book. It was such a delight to win the giveaway and get this gem in my mail, especially since I've been looking forward to this release for quite a while. That said, I truly do not know how to review this book - I shall do my best.
Having read, and enjoyed, Cloud Atlas I felt prepared to tackle another sweeping six-part Mitchell novel. Interestingly enough, while this is overall a less abstract and more unified story I can't say I found it as rewarding nor compelling. One of the biggest problems I have with this book is the feeling that it just doesn't quite hang together correctly. After four sections of story containing hints of magic in the background you find yourself in the fifth section being bombarded with full blown Fantasy, complete with too much terminology, exposition, and mustache twirling villains. It was jarring. It made me wish the section wasn't there at all, or that there had been significantly more of the magical thread running through the other sections. Either would have been fine, but the way it is balanced now feels awkward.
To make it even more off-balance the fifth section closes with what feels very much like an ending, and then you are left with a remaining sixth section that takes place roughly 20 years later and feels like the world's longest epilogue due to its placement. So here is the thing, the all out fantasy isn't working for me. I read lots of sci-fi and fantasy, so it isn't as though I'm opposed to magic showing up in my books. This story however felt like it wanted to be so much more personal, then it blows up into a fantasy epic before shrinking back down again. The proportions are wrong.
Yet even before reaching the ill-fitting fifth section I felt myself wanting to put the book down. The first section had me hooked - Holly's voice as a British teen in the 80s felt authentic, and I found myself invested in her fate. Then the section ended and I found myself beginning all over again. It took me quite a while to get into the second section, and then once again, right when I began feeling invested it ended. This is just part of the structure, so I was willing to grit my teeth and accept it as a part of the overall form. Here's the thing though: the third section, which was easily my favorite, felt like a self-contained novella. It contained a complete story arc, and when I finished it I felt satisfied, even though I was still wanting more. Most troubling though, was that it never seemed to fully tie in to the story as a whole. You could cut the third section out entirely, and it would't impact the overall story whatsoever. Truthfully, I think the same could be said for the fourth section as well, which as many people have pointed out was overly long-winded and self indulgent. (And it knew it - if you want a spot on negative review for this book look no farther than section four where it addresses all my complaints and more. It's very meta.) Still, it's not a good sign when I have to force myself to pick the book up, and I'm relieved when I'm finished with a section (and the book as a whole).
Don't get me wrong, Mitchell's writing is amazing in all of these sections. I underlined several passages, and reread them aloud to my partner. The writing is that fantastic. But the overall cohesion of the story was lopsided and strangely paced. I'm going to be thinking about this one for awhile, but I suspect many of my thoughts will be focused on ways to "fix" it. I'll continue to read Mitchell's work, and I think he's a stunning author, but this particular experiment missed the mark for me.