I'd alwasy vote for wordpress. Far more facilities, better seo capabilities, you can stick loads of plugins into it, and you won't get banned because your email server bounced a spammy 'reverify your blogger account' email from Goolglele
More important than choosing between Wordpress or Blogspot is the "content" you will have on your blog that will determine the level of your success.
I have found Word Press to be far superior. You can also make your domain your keyword and that makes lot of difference
Blogspot is owned by Google. That means a better chance of being indexed . But that's not always true.
personal experience about this, i prefer wordpress, for more control, but for earning content and niche matters.
Wordpress or Blogger-it's up to you as they are equal.Blogger is a little bit more user friendly and easier to navigate.More important for you right now is just to choose one and start.Don't waste your time and start working.
Its not the Blogging Platform but its the Niche and Content that Determines the Earning Rate of a Blog
I would always recommend for WordPress because of its SEO power and many other benefits which blogger can't provide. I have even so many bloggers who has shifted from blogspot to WordPress after working on years on blogger. Experts believe you can make more than 30% with the same efforts with WordPress.
I prefer blogspot, but the most important things is 'content'. Your content must be unique and useful to your audience.