Drupal
WordPress
Reputation
Excellent
Excellent
Single/Group blog/site
Single or Group Blog but with better User Management
Single person or Group users
Ease of use
Little complex at first
Very Easy to use
Admin Interface
Little complex at first
Very Easy to use
Extensibility
Excellent
Not so Good
Blocks
Unlimited blocks and very flexible and extendable
Limited block placement without hacking
Future growth
Can be accounted for very easily due to its vast features
Limited compared to Drupal.
Customized Design
If page design is important to you , you want to choose Drupal
Can customize design but with limitations
Creating content
Easy. But image support is not as good, but can be done with installing TinyMCE or FCKEditor
Very easy. Images can be easily added to the blog
Managing comments and spam
Excellent
Good
Contributed modules
Huge, Many features available
Huge, Many features available
Mulitiple uses
Yes. Drupal is CMS , Blogging is just one of the features of Drupal
Mainly a blog Engine.
Themes
Many themes, but not as much as wordpress
A very huge collection of FREE themes.
When to use Drupal:
v When you want to start with blog and want to extend your website in future
v When you want Group or community building
v You want control and managebility
When to use WordPress:
v If you want ease of use and Navigation and easy to learn.
v You are only building a single blog with basic features.
v You do not plan to expand your blog into a websites