NetBeans is a free, GPL-licensed IDE. It can run on any computer with a Java virtual machine. If a computer has a Java virtual machine (JVM), Netbeans can run on it. Netbeans can, therefore, run on a variety of operating systems such as Windows, *nix, and Mac OS. Being open source means that developers can contribute changes to the code to have the IDE better serve them.

Netbeans not only debugs your code, and points out errors but also gives you hints on which sections of your code could be further optimized.

Has built-in support for the most popular revision control systems

PHPUnit is a testing framework. You can create test classes, run and see the code coverage directly from IDE interface.

The most used composer commands can be done directly from IDE.

You can run Linux terminal inside the IDE.

NetBeans can be extended beyond the basic tool that you get out of the box through community made custom plugins.

Supports Symfony1, Symfony2,Yii2 & Zend frameworks.

Supports documentation generation through ApiGen and PHPDoc.

ApiGen allows automatically generating documentation from specifically formatted comments. It's easy to use, supports traits, allows fuzzy searching for classes and highlighting docblocks using Markdown.

NetBeans provides code completion and documentation for all Twig elements.

Supports synchronization with projects stored remotely through FTP or SFTP.

Supports Smarty Template Engine right out of the box.