This discussion attempts to draw lines between MT and Drupal, showing why Drupal meets or exceeds the feature set of MT.
That's a played-out discussion, though... (and the way to market yourself is not to keep mentioning the competitors)
I'd rather mention THE killer apps for me in Drupal:
Yep. Who cares about the other guys when you can just win people over on features? Comparisons will always be made with other products -- focus on your star features, be honest about shortcomings, point out good examples of use, and let people make their own decisions.