Drupal vs. WordPress for large blog farm project

Curious on thoughts. In terms of creating a ‘blog farm’ with a large amount of cutomization which eventually may have 100K plus blogs, what are the advantages of going with WPMU / MultiSite vs. going with Drupal.

Does anyone here have expertise in Drupal? Do you think it’s possible to pull off a large blog farm with drupal just as well as with wp?

Moving forward with a larger vision, I am weighing costs benefits of drupal vs. wp as developers I work with tend to prefer drupal.

What does WordPress offer than Drupal doesn’t?

Any thoughts?