Here's a good comparison of blogger and wordpress:
and another comparison
and a pretty extensive comparison at computerworld:
the computerworld conclusion:
Both Blogger and WordPress.org are excellent choices for anyone looking for a hosted blogging service. WordPress is clearly aimed at those who are willing to spend time learning its features and can handle an occasionally confusing interface. It offers a wider range of tools for adding content, more widgets and better social networking integration, and superior customization.
Blogger, on the other hand, is much simpler to set up and easier to use; you'll be able to create a blog and manage it in less time and with less effort than is required in WordPress.
So the choice is clear: If you want the fullest set of blogging features, you want WordPress, but if you're looking for simplicity and streamlined blog creation and posting, Blogger is the way to go.