About to start my own blog about Ubuntu on my fresh 11.10 install. I would like to know the pros and cons of using either platform in a Ubuntu environment.
Blogger works perfectly well in Ubuntu (I believe that Wordpress should be ok too, as both are web based).
I recommend Blogger, since it has more resources than Wordpress.com.
Wordpress.org is the GPL version that can be downloaded (but requires a paid hosting service) it's better. But if you want it for free, go with Blogger.
Where will it be hosted? You can't host blogger on your own computer while you can do that with Wordpress. If you'll be using their online services (blogger.com or wordpress.com) for the blog hosting, then it really doesn't matter which from Ubuntu's perspective.
Take a look at these links, they should give you a good head start:
SEO Tip: Customizing Blogger Meta Tag Title
How to add META tags into your blog?
3 Tips To Make Images SEO Friendly On Blogger
How to Add Blogger Sitemap to Google Webmaster
Also, you can Google it for more, there's a lot info and tutorials about Blogger out there.