Magento is an open source shopping cart platform. It uses more than one PHP frameworks. Before you get your hands wet trying your first Magento project, you need to learn some basic concepts of PHP frameworks. There are about 10 top level PHP frameworks and several free CMS like Magento, WordPress developed in PHP language. You cannot master everything. You need to select one or two subjects based on your preferences. Magento is very well structured and is using a module based approach. If you know the structure well enough, it becomes significantly easy to perform complex programming tasks. Magento is good at one thing, and that is selling. Using it for any other purpose would be a waste of resources. As an experienced developer, you can easily learn a new CMS when you need it.