The Secret World's New York City raid for a good while now, and Funcom has finally raised the curtain a bit via a newly published dev blog.
Designer Graeme Lennon (whose previous work includes the Hell Fallen and Facility dungeons) is your guide, and he dishes on the long gestation period for the NYC content as well as some of the lore behind it. He also says that Funcom is trying to strike a balance between endgame challenge and accessibility, and "as a result, the statistical difficulty has not been balanced around full endgame gear."
Lennon explains that the fight features significant mechanical complexity and requirements on par with TSW's tier-one nightmare mode instances. Read all about it on the game's official website.