Yii

If you're looking to develop large-scale web-based applications, you might want to consider Yii - a powerful and efficient PHP framework that comes packed with a rich set of features.

Yii boasts high-performance, thanks to its strictly object-oriented approach that allows you to build efficient and robust web applications with highly reusable components. Additionally, Yii is easy to learn, with detailed tutorials available to help you get started - all you need to know is PHP and object-oriented programming.

Notably, Yii is one of the fastest PHP frameworks around, with negligible overhead when building applications on top of it. And if you're looking to extend or customize Yii, it's highly reusable and extensible, as all its components are self-contained and easily configured, reused, or extended.

What's more, Yii has a rich set of features that cater to every aspect of modern web development, from MVC and DAO/ActiveRecord to theming, internationalization, and localization. Plus, Yii's documentation is extensive, making it easy for developers to upskill in no time.

Yii was carefully designed with serious web application development in mind, drawing on the authors' rich experience in this area, and it's a free software too. Yii uses the new BSD license and supports third-party work with BSD-compatible licenses, meaning it's financially and legally free to use for both open-source and proprietary applications.