Ok, I know this book has seriously devoted followers, but for me it fell flat. Of course, Twilight also has seriously devoted followers, so following isn't always a good judge of if I'll like it.
The Iron King feels to me as if someone who adores fairy tales went "you know what The Labyrinth needs? A love triangle. And Sarah is not nearly enough of a special snowflake, I totally need to fix that."
The feel honestly comes across as almost middle reader to me, except for the bits which are written to showcase the decadence and debasement of the fae. The groping and sexuality is aimed at tween and teens, but the writing reminds me of the sorts of descriptions I used to come up with when I was a tween and trying to write like an adult (this scene is totally sexy and dangerous... really!).
Had I discovered this when I was a tween, I might have been a believer. As an adult, I'll go back to Seanan McGuire, or even reread Elizabeth Bear's Promethean Age novels.