The strength of this series, and it is a mighty shining strength at this point, is taking the "band of wacky misfits" cliche and broadening all the characters into complicated human beings. The Buffy-gang is not together at this point, because the serious shit they've uncovered in previous books involves several of them in different ways, and you don't just come back after 44 minutes of that, form up, and march away through the Stargate into the credits. (Sorry, show slippage.) Even more serious shit arises in this book. We get more of Ex's background, in the form of his old Buffy-gang -- who have shit of their own to deal with. (The new-introduced characters are as solid as the series regulars. Best Catholic priest I've seen in years.) And, of course, we start to get some insight into a character who's been on-stage since the beginning, but not... up front.
(My secret theory of where the series is going is neither confirmed nor denied, to date.)