4.3.4 is the latest stable and recommended production release from Liferay.

Release Notes: http://support.liferay.com/secure/ReleaseNote.jspa?projectId=10014&styleName=Html&version=10250

SVN Tag:
http://lportal.svn.sourceforge.net/svnroot/lportal/portal/tags/4.3.4/

It includes many numerous performance improvements and bug fixes. The most notable is that our Lucene indexing is about 1000% faster now. Numerous issues with upgrading from 4.2.x to 4.3.x in relation to Jackrabbit and other databases have also been fixed. This release also includes UI improvements that go across the entire portal and specific improvements to our Blogs (as in, we're eating our own dog food now, so expect our Blogs to keep getting better).

Thanks go out to our community, our partners, and our employees for making this release possible.