At first I thought this supplement was okay, but after looking at it closer, it has an inexcusable amount of balance issues in its subclass additions. It seems that no thought at all was put into whether the classes would actually be playable or multiclassable or not—only that they sound like cool concepts. There's a bard whose only ability is opening traps. There's a cleric who gains advantage on death saving throws at level one. There are unnecessary and nonsensical cross-classes like a spellcasting barbarian, a rogue wizard, and a religious rogue. There are abilities that are ridiculously overpowered (for example, "You can use a bonus action to make a Perception check to notice hidden enemies. If you notice one, you can move up to half your movement speed and make an additional weapon attack against that target with advantage and an additional 2d8 damage dealt to it." I'm not an expert class designer, but anyone can see that these are absurd and not much thought was put into their balance or even use at all.
I was also turned off immediately by the number of typos in the piece, as well as the clunky organization in some places (the feyblood race lists "advantage on saving throws against being charmed" in two separate places, and the "critical hits" bonus rules are listed under "Character Options" in the table of contents rather than DM rules) and a lot of the sections just seem unnecessary. For example, the critical failure and critical hit tables go on about variations of the same mechanic, such as pushing the target 5 feet away, 10 feet away, and 15 feet away; pushing the target 5, 10, and 15 feet away but knocking them prone, etc., and cycling through the various conditions in the game. I think those types of critical failure effects could be easily made up on the fly—there's little point in making an entire table for effects as uncreative as they are. I guess I just expected more.
The magic items are hit-and-miss—Some are pretty inventive, while others (like almost all the subclasses) seem somewhat juvenile in their ideation.
The backgrounds were somewhat underwhelming, as was the new feyblood race, and the sanity and suspicion rules are needlessly complex, especially for 5e; I did like the list of story items and the death and returning rules, and the lingering injuries bonus rules were somewhat underdeveloped, but inspiring.
I cannot recommend this, especially for its high price. I was deceived by its professional outer appearance and judged a book by its cover, and regret purchasing it for how little I got out of it.
[2 of 5 Stars!]