eZ Platform is an interesting option for a new CMS built with the Symfony CMS. It is not built using the Symfony CMF toolchain, but is a separate content repository and configuration level for the Symfony Framework.
eZ will roll out its biggest release in over a decade, eZ Platform and eZ Studio, at the end of 2015, with progressive development throughout 2016 and beyond. Based on the Symfony2 full stack framework, eZ Platform offers developers a fully open and extensible CXM core with fully featured APIs. eZ Studio, a commercial offering, rests on top of eZ Platform and simplifies how content editors manage landing pages. Together, eZ Platform and eZ Studio make up eZ Enterprise, eZ’s new enterprise offering, which is bundled with support services.
Learn more about the fully featured Symfony CMS
Sulu is another option for Content Management when using the Symfony Framework. It uses Symfony CMF and a PHPCR content repository to provide content management powerful content management features with a slick user interface:
Sulu is a content management platform based on Symfony made for businesses. It’s a flexible CMS to create and manage enterprise multi-sites and a reliable development environment for high-performance apps. With powerful features for developers and a simple UI for editors it’s the ideal engine for state-of-the-art business websites and web-based software.
Learn more about Sulu, the Symfony content management platform