One key-benefit of TYPO3 has always been its flexibility when it comes to integrating 3rd-party systems. And the upcoming version 5, based on the FLOW3 framework, will take it one step further: The just implemented Vendor Namespaces support lays the foundation for a seamless integration of components such as Zend Framework, Symfony 2 components or your in-house developed proprietary library.
Robert outlined FLOW3's Vendor Namespaces support in a <link http: robertlemke.de blog posts flow3-supports-php-vendor-namespaces>blog post.