On the Symfony blog, there's two new posts highlighting some recent improvements to the Symfony2 framework - the addition of static page caching and payment validators:

• Static page caching support in the routing configuration
• Payment validators with docblock assertions, including error messages for failures.

These features are all a part of the upcoming Symfony 2.2 release that's planned to be moved in the "stabilization" status in early 2013. It should be able two months following that when the stable version will be released.