The armor looks cool but to be honest, I hated everything about the Nightingales, as well as Karliah and Nocturnal.
I agree. I absolutely love the Nightingale armor, but the whole thing went no where. I basically sold my soul to Nocturnal for no reason. I did like the twist in the questline but the Nightingales was a disappointment.
The armor is so cool and perfect for what my character needed that I think I'm willing to look past the lack of ideas behind the quests.