I think you should consider a few things before making a decision.

1. Are you sure you want to use symfony for your project (if you need quickly working solution probably it makes sense to use Joomla bundled with forum/social components which have all needed infrastructure). Or if you are more experienced with Drupal you could go with it as well

2. What specific CMS features you are looking for? For most of mentioned CMS I did not like that fact that they use inline editing which at some point complicates content management (so if you need something to add articles probably makes sense to use your own code to handle that – which is very quick to develop)

3. As far as I know – Apostrophe is really one of the most populars such CMS and you can build it into your project (you can do it with the other provided CMSs as well though)

Hope it helps

I haven’t used any CMS before (but I use Symfony and love it and I’ll have to build a site with a lot of features that a CMF can manage (forum, news, personal blogs, events). But it also requires especific features (messaging, courses and groups associated to a professor).

So, wich one of these CMFs would be better for this project? I’m thinking in Apostrophe, because it seems I can add it to an existing project with my own modules, can I do the same with the others?

Thanks

Cheers

Check it out here:
http://www.robertspeer.com/blog/apostrophenow-a-cms-so-easy-even-your-mom-could-use-it/