I haven't tried Blogger, but I know that WordPress.com doesn't get in the way of experience. Except for not allowing you to use certain HTML elements (iframe, script, embed) which can potentially pose security risks to both the site visiters, and WordPress.com itself.
You can, of course, host your own blog (using the WordPress.org "software"), if you wish to mess around with the HTML with unrestricted access (for those of you who love [ab]using iframes). Be sure to add a few WPCache-like Plugins for speed, and woosh. (If you don't use WPCache, your site may run way slower than it potentially can, apparently.)
Commit to LEGO Mindstorms Robotics Stack Exchange:
Commit to LEGO Stack Exchange: bit.ly/Area51LEGOcommit