When it comes to creating a free blog, one has to choose which service to use. There are two heavy weight contenders: Blogger and Wordpress. Blogger is as easy to use as email this is a big pro. Built in templates virtually eliminate the need to learn coding. Wordpress, on the other had, gives the blogger many more options for customization especially concerning plug ins, a pro for Wordpress. One of the differences between the two contenders is that Wordpress allows you to blog from your own server where Blogger constrains your blog to their server meaning your domain name will be thisisme.blogspot.com. Another big difference is that Blogger doesn't allow you to categorize your blog articles. This is a big pro for Wordpress.
Blogger is designed for the person who wants to publish their content without much hassle. For the professional bloggers, your more apt to use the more customizable features found in Wordpress.
I found a great comparison chart on Pulsed.