Yeah, Six is definitely more like a concert. I've actually heard that, while MJ is PACKED full of songs, it's actually a much better and deeper book than your typical bio-jukebox flair. Another thing to keep in mind is that Intimate Apparel is an opera, not a musical. I've seen Six and did enjoy it (although it sounds like the easiest one to eliminate for you), but I've heard good things about the other 3.