As an enthusiast of all things hag-related, I waited with baited breath to acquire this gem.
The new options give a lot of customization to witches, changelings, and coven casters. Pleased to see changeling options for the outsider hags and finally (if not a little brief) new information on hag goddesses.
Interesting to see how different casters and psionics can touch upon the feats, spells, and items. Also pleased to see more classic hag homages, Curse of Dragonflies screams Spirited Away.
All of the Blood supplements have been useful, and Blood of the Coven especially so!
The overall concept of this adventure path is by far my favorite and it shows horror in a light not often utilized.
There is a such a sweet satisfaction when a player's mindset goes from just bashing another skeleton to the mortal chill of facing something that has crawled its way back from the veil of death and is intruding upon the natural cycle of life, and Haunting of Harrowstone kicks off that feeling in a superb manner.
It is going to be captivating to see how the story unfolds, and I am just as anxious as my players to see what is in store. Very brilliantly done.