Beta 3 is currently under development, with lots of small fixes and a few other minor changes. It is scheduled for release before the end of March.
There will be a period of about two weeks between beta 3 and the final release of version 1.0. This will be for bug fixes only.
So the short answer to your question is about a month from now. But you should feel confident installing/modifying/integrating beta 3. As always, the upgrade path will be very smooth.