Oh, and I forgot to mention Stack Exchange:

StackExchange is a great example of community-driven, developer-level support. WordPress Answers launched 7 months ago, and has 11K questions, 16K answers, and 7K users. Drupal Answers launched less than a month ago, and 4.6K questions, 6.6K answers, and 2.9K users. Joomla answers is currently at "failure to launch", not having yet even reached the Beta phase.

Advantage: WordPress