From what I have seen Joomla is a better CMS. Wordpress is a blog that is used as a CMS, whereas Joomla has always been a CMS. It seems real web developers like Joomla better. However WP does make it easy to deploy advanced site functionality off the shelf -- thus personally I like WP better
As Compare to Joomla, WordPress is more SEO productive because themes in Joomla are less SEO friendly as compare to WordPress which come with all latest feature and rules of Search Engine Optimization.
That would depends what kind website you're going to develop. Joomla is very powerful cms system for content management. The admin panel is well categorized with rich features for any content requirement.