[lemonberry]

In a nutshell: it's a hell of a lot easier to get going on than Drupal. I've been developing Drupal sites, along with much more experienced (general and drupal specific) developers for the past 6 months. And it's not easy to get going on.

Also, Drupal is often coined a CMS. If you google "drupal is not a cms" you'll find a number of people referring to it as CMF - content management framework. It really allows you to build a custom CMS for a specific purpose rather than customizing a CMS for a specific purpose. It may sound like semantics, but if/when you have a few Drupal sites under your belt you really get what they mean.

[edited for clarity]