The current PHP world has been infused with lots of MVC frameworks like Zend framework, Codeigniter, Laravel, CakePHP, Symfony, YII and many more. PHP developers are able to choose any of these or others as per their coding style or whichever is best or easy to use or secure. In India, Codeigniter and Yii are widely used because of their simplicity compared to Zend framework, Laravel and Symfony. However, its not just enough to use any of these framework and call yourself an MVC expert.
Unless you use an optimized / efficient / effective OOPS philosophy, you are incomplete. So one such philosophy or paradigm is the famous S.O.L.I.D. priniciple which enables you to come up with an optimized way of implementing an OOPS based framework. To know more about this, click here