I feel rather bad about writing this, but I kind of think the series has lost a bit of its steam.
I was rather upset (around book 4) when I realised the series was going to end with book 8. But since the beginning of book 6 I feel like, yeah, you know what, it probably is time, after all.
I suspect at least one of the authors don't feel all that into this particular setup of characters any more - and it shows.
Zoe has become more and more marginalised within the latter books. She flashes by in kind of short POV chapters, while others, previously only side-kicks, get more and more attention. It is very obvious some new constellations of characters are in the works, behind the scenes - in preparation for other book series, and mentally, I suspect the authors were already there when writing this book.
Don't get me wrong, I'm still very fond of this series and especially the way it feels like returning to a really good TV show every time I press Play on a new book, but I'm not entirely sure I will branch off after the last Zoe Finch book to check out all the other books in the same story-verse.
We'll see though. I might change my mind in the future.