Well, My answer is wordpress even though blogspot is the product of Google. Reasons: If you use WordPress then you have full control on your blog rather than blogspot and WordPress auto Ping request and Sitemap that tells Google to take the latest update.
I also go with Wordpress. It is very SEO friendly. What with specific plugins for SEO. I started out with blogger and now use Wordpress, so i sure can tell the difference.
Wordpress is great for SEO, also have you thought of WPDirect? some great SEO plugins to help you make your website search engine friendly
I have a blogger account and my own wordpress on my own host. I prefer wordpress but just blogger as a private journal, which I think it's perfectly fine for that purpose.
We have a huge thread on same topic. This sticky thread will give you lots of information: http://forums.digitalpoint.com/showthread.php?t=1518279
wordpress will crawl faster then blogspot... this is my own experience with wordpress... wordpress consists one plugin which is itself ping the blog directories and that is the advantage for wordpress users to get their page crawl faster...
Word press is more effective than blogspot blog, but if you try to post duplicate content in wordpress your blog will gone out. If the content is unique you will be the top on the SERP reults
Wordpress because you can add meta tags in your post, your post will automatically be pinged and also sitemap can notify Google. So, without any hesitation, i shall say that wordpress is the best in this regard.