It appears that I’m a little behind the rest of the blogosphere, so please check out Edward Roske’s blog for new features in EPM 11.1.2.3:

Look Smarter Than You Are: All the Cool New Features in Oracle EPM 11.1.2.3.

Conventional wisdom dictates that you might not want to go live in production with this release right away.  To evaluate the release, it would be just fine for a development or sandbox system, though.  Typically, once the first round of Patch Set Updates (PSUs) have been released, then it is considered ok to roll into production.