I have to largely agree with Roget here, although I am upvoting.
There was very little done to differentiate their beliefs and practices, and outside of the component of a person being "ridden" that was never really important to the narrative. For a strong example, the section on deities saying "x is their version of y, a is to b… Etc" with only minor differences marked in footnotes made me think, "ok, so they're just straight Sarkics."
The history was alright, although just having one interview and it being full of exposition somewhat underutilized the format. (However, I realize I'm just comparing this to the other two articles, and that isn't fair. Innovation is a good thing.) I don't really feel equipped to comment on the slave narrative.
I really enjoyed the "mundane" details of their sectt's life and composition, which made me think of vampire tropes in a very enjoyable way. I'm upvoting based on that enjoyment and by the kick I got out of the ending story/twist, which was pure Cthulhu Mythos and unexpected.