When Digital Catalyst first looked at web development frameworks that it considered a number of proprietary frameworks as well as the big three open source frameworks (WordPress, Joomla and Drupal).
We ultimately choose Drupal for its strength in the development community, superior security, organic search engine potency, and feature scalability.
But it is important to spend some time looking at the other contenders.
As at Feb 2014, there were almost 75 million WordPress sites on the web which represents a staggering 19% of all websites on the planet. Why? The cost of delivering a WordPress is often up to 50% cheaper than Drupal to configure to get a basic website into place.
Drupal pays for itself in the longer term. The WordPress framework is cheap to get going but will cost later if not done properly.
This article presents the true cost of a WordPress site:
http://efficientwp.com/the-true-cost-of-wordpress-maintenance