Depends nearly entirely on skill, timing, and how well you built your build. I've seen juggernauts destroy marauders. And marauders destroy juggernauts. It can be done either way. I disagree that one of the classes would completely outperform the other.
While this is true, a marauder still has the upper hand in a theoretical, even setting. It is as you say. Player, gear and talent setup matters the most. This post makes it look as if jugg is a worse class, which is not the case at all.