I have always used Wordpress in the past, and it has been great. Having said that over the past week I have put together a Joomla site. I have to say Joomla is pretty damn nice, it is a lot more powerful than WP. There are a ton of plugins & modules that make stuff very clean and easy to do. The latest ver of Joomla is SEO friendly too.
It takes a little time to find your way around the control panel because there are so many options. My recomendation for anyone wanting to try Joomla is, first off only use it if you need a CMS with a lot of nice features, if you only need a blog type site, stick with WP. Second, if you are going to go with Joomla, buy a template from a place like RocketTheme because they will give you an install that will load Joomla, the template and all the sample content to make it look and work just like their demos. This way you can see where everything is at and how everything works.
Joomla is very cool once you get the hang of it....much more flexable that WP.