Wordpress is a blog system not a CMS, so you can't compare joomla or drupal with wordpress.

I have tested a lot of CMSs but have found Joomla as the best one.
Reasons:
1- Ease of use and setup
2- Great layouts
3- Most active community
4- Most number of add-ons available
you can find extension or component for almost anything.
5- Most number of templates available (Commercial+ free)
and a lot more things, where other are way behind.