This infographic shows why WordPress wins "hands down"
I'm often asked this question by marketers taking their first steps into blogging as an individual or for their companies. These days I always answer without hesitation "WordPress"!
My justification is based around the experience you can create (WordPress has great themes or is readily tailored); ease-of-use (as easy as Word or Pages); extensibility (plug-ins?); scalability (can it grow with us?); support (many agencies and freelance developers support it) and cost (it's open source, you only have hosting costs).
This infographic provides a more qualitative assessment to support these arguments. The market share figures really show how WordPress dominates. The average day sees an average 500,000 new posts on WordPress.com, not to mention the many sites, like Smart Insights that run a bespoke hosted version for their blog or full content management system.
If you're a WordPress user already, check that you're using the Yoast WordPress plugin for SEO. We are and it's awesome!