This release incorporates all of the GNOME 2.11.92 (aka. RC1) Desktop and Developer Platform, including glib/gtk+ 2.8.x and cairo 1.0.
This release also includes a number of the recent fixes to GARNOME Makefile's that Joseph posted to the mailing list and some SMP build issues have been resolved.
That said -- and while this release has actually been more stringently tested than it's snapshot counterpart -- it's still likely to do things that are weird and unexpected ... maybe ... that's just the nature of the beast.
In particular, GCC 4.x users may want to take a look at:http://bugzilla.gnome.org/show_bug.cgi?id=309661
and then uncomment the CFLAGS workaround in your gar.conf.mk file before beginning your build. Aside from that, READ the README's, join the mailing list, use the IRC channel -- and most of all, report bugs -- all of which will help make GNOME 2.12 a happier and safer place for everyone.