Who is more brave, cowardly? Kurtz, who faces his inner self and goes over the edge, or Marlow, who goes to the edge of the abyss but steps back?

This is really asking for your opinion rather than mine. I think Kurtz got sucked into dellusions of grandeur. He really did nothing for the natives. He exploited both natives and their resources. At least Marlow was sickened by the whole experience.