My question is about the fast storage into RAM. Actually my project is a big symfony2 app, and I use a lot session storage (Symfony\Component\HttpFoundation\Session\Session). I'd like to try something else because I'm not totally happy with symfony2 session since it stores only simple types in it, objects are not allowed. I did a search and redis seems to be the perfect choice BUT someone suggested memcache.
Could memcached be better than redis? Is redis worth a try (despite the learning time we've to spend on it)?