Along with the Zend Framework and CakePHP, the symfony web framework is considered to be one of the PHP “big three” frameworks. Having personally used it for a few projects, I can vouch for its power, flexibility, and ease of use, and in fact am so enthusiastic about it that we published the definitive book on the topic (written by symfony’s creator and lead developer) just a few months ago.
This week the project took another major step forward with the launch of symfony Forge!. Intended to be a central location for community plug-ins, discussion, and other tools, if you’re using symfony I strongly encourage checking it out.

Apr 20, 06:19 pm
I’m a bigger fan of the Zend Framework personally. Although the Symfony project seems to be shaping up nicely; I genuinely believe the Zend Framework is quicker to get to grips with. It also seems much easier to deploy the framework as you see fit. Which ultimately leads to happier clients!
I guess it all boils down to personal preference and speed of development (probably in that order!).
Jon.