Bestiary 2 before Chronicle for me. I can live without a discussion of full-on Immortal campaigns for a short while (okay, we know this is U_K we're talking about here, but still...) while using just the adventure ideas from the first two volumes of monsters when I need adventure ideas in this realm. For me it's a question of teasers, I suppose- he's been teasing us for months with mentions of the beasts that are coming in the second volume, like the Bi-Sects and other Entities, the Lipika, and several others, and I want payoff.

There's also the fact that by the time Bestiary Volume 2 comes, we'll have the full rules for Ascension and Grimoire ready to use, so between the expected adventure ideas coming with the new monsters and everything in those two rulebooks, we should have plenty of adventure ideas to spark the imagination.
I expect it will take some time to transition a game from a simple Epic-level mortal one to a full-on Immortal game anyway, so in my case there's time for waiting.
Naturally, that's just me, others may agree or disagree as they choose.