I asked the same question a long time ago on mylot and it seemed more people favor WP so I went for it. I noticed it gets indexed by google faster. But later on I realized that if I want to monetize my blog I better go with blogger so I switched. Lately I found some tips and ideas how to get crawled and indexed by google real fast and tweak your html tags so it would be more searchable. With WP you can't play around your html if you're a free user. So now I'm sticking with blogger.
is it possible to place ads in a free wordpress blog, with xxx.wordpress.com domain? or you need to pay to have full functionality like blogger?
I think that it depends on what you are hoping to accomplish. I currently use both. I thin that blogger is easier to use, but you can get a lot fancier and more professional looking sites with wp. I know that they both pretty popular in the eyes of g00gle. Nut the main thing is to make sure that you are putting out unique quality content. If you are not doing this, it really does not matter what you are using. To Your Success...
I smell BS. Why would Google choose to rank a rival blogging platform higher? Just cos you had a bad experience with your site, doesn't mean everything will be peachy with WP. Sweet jesus! They allow you (in 2mins) to switch over to your own domain and you also have the choice to host the site elsewhere.
I prefer Wordpress, as I'm more familiar with WP and I think WP is also easier to manage than blogger...