I'm biased towards WordPress....I love it. It can take some time to get used to when first starting out, there's so much functionality within that CMS, but once you really start using it, it'll get easier. Plus, for most things you want on your website, there's usually a plugin or theme that does it for you. If you have plans to enhance your blog to even a full on website, it's fairly easy to develop what you currently have to that. Bottom line, I've found that WordPress offers more flexibility.
Regarding Blogger... I like how it organizes and connects all your Google products. Creating posts and getting your blog set up is pretty straightforward. Although no one knows for sure, I think having your blog on a Blogger platform may possibly put you in a favorable position towards SEO and ranking on Google.com, but like I said, it's not known, it's just a theory I have.