Let's share some memories. Can you remember what the first CMS you worked with was? The first one I tried was Mambo (that was how Joomla was called, before the developers split). Later, I started using php-nuke and Wordpress.
I have some experience with Wordpress and am looking forward to making use of its versatility afforded by all of the plugins. I am not familiar with Mambo but have heard of php although I have not used it as of yet.
I remember to have worked with Magento CMS for the first time. It is more of an eCommerce CMS that provides with a perfect platform to create the perfect business website and manage it efficiently.
I started my first website on Joomla, and I use the CMS for quite awhile till I got used to it. Now I, like any other webmaster, prefer to use Wordpress, .
Wordpress is the first CMS with which I worked. Joomla seems to be very popular as well. I believe the key is to find which one works for your specific needs.
I also worked with WordPress first. I think it is the perfect blogging and content management platform that also enables you to create a website. It is free and extremely easy to use. It has a wide range of themes and applications that can be applied easily.