I have a really hard time falling asleep if anyone is making noise in the room at night. I invested in these. They really did help me fall asleep every night and would keep basically all ambient noise out.
They're not completely noise canceling -- really loud sounds can get through. I would still hear sirens that were right outside the window or loud talking. But they do a good job of filtering out all of the little noises, rustling, snoring, whispering, etc, that are common in shared spaces. Will definitely be using these for the foreseeable future.