[cj iwakura]

-Music (I love hearing the new songs they find, especially ones I've never heard)
-Videos (The hardest thing about sight reading for me is I always try to figure out the stories at the same time)
-Stepcharts (No double-charted game in the world can touch the awesomeness of Freestyle or Nightmare yet.)

And to a lesser extent, freestyle appeal, since no other dance games seem to have charts that can work with routines.