They're finally out, and both of them contain security fixes for 2 Beta 4 and 1.1.7 respectively.
They also have the benefit of several bugfixes, particularly for RC1 but also for 1.1.8.
Everyone, even SMF Charter Members who had access to the RC1 preview, is advised to upgrade to these latest versions as soon as practical. You should not continue to use 2 Beta 4 or 1.1.7 any longer then necessary.SMF 2.0 Release Candidate 1 is out! SMF 1.1.8 released!
Go get 'em.