They've all got their uses. Wordpress is the most powerful and most flexible. tumblr is great if you're a hipster or 15 years old. Or if you don't want to setup Wordpress. Blogger is bottom of the barrel in my opinion.
Before coming to Vivid, I did web development work and I still do some stuff on the side. Wordpress is by far the most powerful, most flexible, and for me it's the easiest to work with.
Here's our blog, built on Wordpress.
VividRacing.com Performance Racing Parts