I think the next release of 5.2 will be a release candidate. The last word I heard from the developers was that there were two or three bugs to fix before the release. So it will probably be at least a week or two before the 5.2 RC is released and then a few more weeks after that before 5.2 stable is released. Of course, any newly discovered bugs could delay them or prompt another beta release before the RC or Stable releases.
I have a last question about the new version (5.2). It said that Sphinx storage engine is included in the source, and here is explained how to install SphinxSE: http://kb.askmonty.org/v/sphinxse But, is installed Sphinx (indexer, searchd, etc) with MariaDB? or we must install Sphinx apart, and after that, install the SphinxSE plugin? Regards! Enrique.