Find my full review here
This is a fantastic resource for DMs and players, bursting with new character options for clerics and paladins (and even a scattering of druid and ranger archetypes). Honestly, you'll get a lot of value from this book at the price.
The content is mostly well balanced (if anything, sometimes it's a little too conservative) and there's hardly anything in here that could be exploited to "break" your game. There's one particular spell which deals damage and can be cast as a ritual, which is a big mistake, but that's about it.
I would allow most of the content in the book in my game with very few reservations, and the rest could be easily adjusted with homebrew or simply monitored as we play to see if my reservations are undeserved.
I really wish this book assigned the spells to class lists, because it's such a waste for them to only be available to a cleric or paladin of a specific religion. In practice it means a lot of the great content is inaccessible to your players in any given campaign, which is a crying shame and a waste of the designers' considerable efforts in creating them. I ended up assigning the spells to class lists myself, and the table is available in the form of a googledoc for anyone else who'd like it. Find it here.
I've also compiled a list of editorial errors and personal feedback on various things in the book, which I hope the designers find useful pending any future errata. Find it here.
[4 of 5 Stars!]