I had trouble seeing the screen through my Darth Vader mask, but I'm pretty sure its good. I would recommend going as the R2D2 if you're a midget or maybe some humanoid, because it makes it way easier to eat popcorn. I was knocked over in the ensueing dash for seats, so you might want to make sure your outfit isn't too top heavy. Also, if you go as this guy:
it doesn't look as bad if you want to eat others fallen popcorn off the floor.