I really love the system, and the game play is great. It is one of my favorate D20 systems, and the setting is great too. If you like 5E D&D, you will like this. It gives players a lot of options for character creation while balancing the classes (paths) for the characters better than how 5E does it. I will say that two things bug me about it: lots of splat book and the tone of the fiction doesn't match the tone of the mechanics. These are minor gripes... but to be fair let me explain.
There are a ton of splat books that provide a lot of additional options for players; which is good... but each splat book is its own very specific section of options. On the one hand I like how focused that is as far as the topics (all fae in one, devils in another...), but I dislike how there is a lot of GM info, like monster stats and certain lore info that deals with things that are secret to most of the people of the world (like who the Old Gods are and who the New God is) within these products. I would prefer to have seperate books for player options and DM Splat matterial; that way one can make a preistess of the New God without nessicarily giving away his true nature in case your players don't want to ruin the surprise (or the DM wants to use the surprise).
Second, the mechanics don't support the tone in my experiance. The tone in the fiction and lore of the book is bleek to say the least... adventures in the shadow of the demon lord after all. The game play I tried to run the first time rules as written, and I found it to be fairly hard to die. It is not a bad thing if that is what you are expecting, but I was a little disillusioned with how a lot of the game play works out with the base math based on the tone of the product's description. It will take several rounds of chipping health away from each other to decide a combat, and there is a lot of flavor text to the spells, effects, and path abilities that just doesn't come up an any relavent way; ie, the spell Desire's End does 2D6 damage and makes the target's genitals scrivle up and fall off. Kind of a magically punching below the belt kind of thing; ok... but 2D6 is not a lot of Health to be taken off, so this is interesting flavor with no real mechanical bite to it. Weapons do not do a lot of damage compared to how much Health most things have; we experianced easy fights lasting 3-5 rounds with a party of 4 and most creatures are only a threat if you wear down the party over the course of several rounds. It kind of feels like you are fighting with wiffle ball bats. I was expecting combat to be fast and brutal, like GURPS or Call of Cthulhu; this feels a lot more like 5E D&D.
Long story short, if you like D&D 5e, you will like this. It is particularly good if you like to multiclass and spend an hour going over character creation options that turn out pretty well ballanced. It really is a well constructed game to have this amount of variety without leaving anything too unbalanced. I do think it is worth the cost just for the art. You will have to buy a few splat books to get all the options, but nothing new if you play in class based systems.
[3 of 5 Stars!]