I ride wearing a Shoei Rf900, and it is quiter than the 800. I recently talked with a guy in a motorcycle shop. He says that the HJC he has is quieter than his Shoei.
This may have as much to do with the bike/speed and shape of your head.
Too bad the shops don't have a room you could step into the try the different helmets against ambient noise. But then, that wouldn't include wind noise (also caused by the shape of the helmet).