Overall: This movie was a Frankensteins's monster of fabulous parts assembled into a story that ultimately found itself in the uncanny valley of greatness. It wasn't great. It was good. It should have been great, all the ingredients were there and assembled, but it wasn't great. Birdman is cheesecake served with fudge, too rich.
Story: I'm biased against stories with no characters I can relate too. The main characters were all broken in ways that I am not, I had no one to identify with, no one to anchor myself and be empathetic towards the rest of the crooked ensemble. Instead I just watched and was annoyed with them all. Least of all Birdman, suicide attempts are not the path to the hero.
Cinematography: Almost beautiful. Too many narrow corridors, many scenes were way too dark, and a few swooping steadicam shots is fine, but when you build the whole movie around it - no thank you.
Should you see it?: If you like movies like Requiem for a Dream and other "human stories" you'll enjoy Birdman. But I didn't like it, because Birdman is a coward, and I hate the idea that you can become a hero through cowardice.