If you use Joomla! for your web design you probably found yourself in a situation to be looked at like a nerd because why use Joomla! instead of WordPress?
Maybe you even got your job application rejected because they are looking for WordPress guru, not Joomla! master. Is WordPress really a better choice? Here I am not going to compare these two CMS' in details but I will focus more on good things off Joomla! and why I think that it is a better choice. Of course, this is not to be considered as a fair and objective opinion because you can not expect it from a web designer with a "Joomla! forever" attitude.
Joomla! is a full scale CMS (Content Management System) which, from the very beginning, was designed for a wide range of web site types (on the other hand, WordPress was designed as a blog platform). This doesn't mean that WordPress is disadvantaged because it has lately overgrown it's original role. But I think that Joomla is more stable in a sense that it's core structure, which was MVC from the beginning, didn't go through a transition from one system to another but was only developing and upgrading with new features.
About Joomla! and its good community support, frequent updates, constant development, responsive design, user handling, etc., you can read at the official website, (Joomla! core features) but I would like to mention few details a web designer might face in his work.
When starting with Joomla! it is very important to understand what plugins, modules and components do. Modules are great in cases when texts, images or login forms need to be placed at a particular position on a website. For example when a main menu needs to be placed at the top or in a sidebar. This is possible to achieve with some plugins using short codes (like with Sigplus gallery), but plugins are designed for system tasks "under the hood", not directly exposed to visitors. Authentication, editor settings, gallery preferences, spam protection, onsite searches are some of the tasks plugins are design to take care of.
Components, on the other hand, are real applications which also can perform system tasks (i.e. Sleeve Backup), or they present a complete user interface for administration of galleries or contact forms. Contrary of modules and plugins, components can be linked to directly from a menu item (in the menu item preference you can choose a specific component to show when a visitor lands on that page). A good understanding of this concept is almost a half of the skills you need for Joomla!. This is important when a component comes with a module, or when a module comes with a plugin, you need to know where to find settings for specific tasks.
Joomla! administration interface is maybe a bit confusing when you open it for the first time, and maybe it requires a steep learning curve but it is meaningful and sufficient for simple websites which you can design without manual coding. But of course, in case if you do need manual coding, an MVC structure of folders and files on a server name it easy to find a Modul which needs some CSS designing. It is easy to find a folder with modules or templates and edit files, but for templating you don't even need to leave the administration which comes in handy when you don't have access to FTP or server.
Joomla! MVC structure makes it easy to find and edit files
Language support is pretty good, but if you need to fix a phrase or two this can be done easily without installing some specialized add-on. To override a certain phrase you only need to find the string via built in search engine and then write your own phrase instead.
Overriding language phrases is easily done in Joomla! administration
Eventhough Joomla! is highly sophisticated its strength is not only its administration and architecture, but also a large base of extensions, of which many are free. In first years, it sometimes happened that extensions didn't perform well, but as developers gained experience and as the system grewmature, extensions became more reliable in their performance. JED (Joomla! Extensions Directory) contains a little over 9000 extensions, which is far behind the impressive number of plugins for WordPress (around 20 000), but still it is enough for nearly anything you as a designer might face. When we talk about security, multimedia, communication or design, there is an extension for it. And I repeat, a large number of extensions are free and open source code with a fair support (commercial extensions get better support but some developers of free extensions are willing to answer you email). Components are mostly straight forward and those more complex usually come with a detailed documentation which makes them easier to handle even if you use them for the first time.
Templates is the topic I don't want to talk much right now. Because there is a large number of them, just as it is for WordPress. It is true that often I couldn't find a template which would satisfy mine or clients needs. For that reason I focused on frameworks, specifically Gantry framework. A framework is not merely a template, it is a whole template administration for tweaking styles, fonts, layout, link colours and even website background. There are free and commercial frameworks. I I would recommend frameworks to serious web designers because knowing them simplifies templating because there are things that you don't need to program by hand. It's like working with Bootstrap which comes with predefined features. I prefer Gantry which attracted me with a rich layout. It is developed by Rockettheme which designs extensions and templates for Joomla!, WordPress and Magento. There are not many free templates though, but a real designer designs his own template anyway.
At the end it's worth mentioning that Joomla! doesn't fall behind WordPress in SEF. In new versions search engines can index image folder in order to index photos but even before that Joomla! was optimized well for search engines.
Maybe this article didn't convince you that Joomla! is better than WordPress, but it didn't have to. Here I just wanted to share some experience and why I use Joomla! and went I think it's better. This is introduction and in some future article I will write about specific and problem solving.