It's been in the tree for a month now, with no bugs for a few major versions and a lot of testing happening in Gentoo. Also, it's been switched to by default in Funtoo with no problems that i've seen arise on their bugtracker or forums. Arches, go for it. Thanks.
amd64 stable
x86 stable
arm stable
ppc64 done
Stable for HPPA.
alpha/ia64/m68k/s390/sh/sparc stable
resoling. obsoleted by bug 427680, ppc, please continue with that bug.