I have only set the Brightness specifically where the test disk, test pattern, or pattern generator told me to set it. I learned a long time ago that trying to change settings from broadcaster to broadcaster is impossible. The Best you can do with all calibrations,where broadcasters are concerned is to find the Top 3 channels that you watch most and then split the differences between those 3 and live with it. I have a Major Broadcaster in my area who can't even get all their Cameras to look the same when they are doing the news. As for DVD players I set them up one time with meters, test patterns and live with it, till I change it out.
Black levels are so hard to get to look right sometimes because of Director's one time they want you to see deep and other times not, so they will play with brightness levels right in the middle of something.
So to answer your original question. Sometimes a little crushed Black makes 90% of the rest of my picture look better . My personal opinion is the if I have to error on one side or the other I usually prefer a slight crushed black.
But when it's right by manufactures Display and Video media it is a beautiful thing.
Nothing's Impossible if you don't have to do it yourself ! Glenee