According to me there are two popular CMS – Joomla and Drupal. (one can argue WordPress is the best CMS) I think the new version of Joomla is not good because they don’t seem to have inbuilt feature of ‘search engine friendly’ url. Joomla mentions many extensions but nothing worked for me easily. In fact just last month I had to move karnataka.com from Joomla to Drupal for this one reason.
You can see the URLs on BJP.org being very unfriendly even for humans – For e.g. their IT vision URL is http://www.bjp.org/index.php?option=com_content&task=view&id=2794&Itemid=394 instead of something like http://www.bjp.org/elections/lok-sabha/2009/it-vision/
Anyway it is good to see a major political party embracing the internet and mobile in a big way and opensource is the right way.