What I especially liked this book was the effor to make all that 3.5e content feel like it belongs in the 5th edition. Everything feels properly re-imagined. As a DM I doubt I'll get to use the classes, though I do very much like their feel. What I'll definitely be using is the long, long monster and NPC listing. Some of these would make excellent sidekick characters and add some excellent flavour for the more strange locales with mysterious powers. And there is quite a bunch of them.
What I also liked to go through in detail were the pieces of lore and fluff to apply. They exist especially for Eberron, but other settings get their blurbs as well. I've already found a couple of ideas to use soon in my current game. As always, The Korranberg Chronicle series delivers in a way that will bring me back repeatedly for the reference material.
[5 of 5 Stars!]