Yes, you can see the parades and I've heard that its only noisy during the parade that otherwise they are quiet. Keep in mind though, the same type cabin is right across from you and you can see in their cabins, so the same holds true to yours....I think the increase is worth it over an inside.
We have had both rooms.We enjoyed the promanade room just to sit in the window and watch as people walk below.We enjoyed them and there were no problems with noise.It is also good to watch the parade as the crowds on the promanade can be heavy.
As for the inside rooms we also enjoy them,because we like to sleep in and the room is dark.We have been on 10 Voyager class cruises.
If you do get the promanade room as Donna said close the curtain when going into and out of the shower.