I been working with newest stable version of Joomla… The Joomla 1.5.3 Stable Full Package, like all other Joomla version, the recent Joomla installation is easy for begginer. This version is more faster and really seo friendly.
The administrator panel and all ajax functionality is simply amazing. The user interface was so brilliant, while the component and modules are easily to navigate.
If your beginner on PHP I don’t recommend Joomla, on this newest version, you will need at least intermediate knowledge on PHP. The template system are more complex and revolves around classes and different function. The new API’s are powerful but I think like other CMS this is lack on documentation. I have to asked Gerry for some reading of classes and functionality.
To learn more about Joomla you should read the books Mastering Joomla! 1.5, I choose the book because I use Joomla and followed the transformation from 1.X to 1.5. As anybody using Joomla will know the platform went through some pretty steep changes for the better and the online documentation is a bit unhandy to use.
Anyway you can also check the Compass Design Article on How’s to Create Joomla Template.
Joomla for me still the best open source Content Management System but WordPress still the most powerful blogging tools.