@Albertus At this time there is no defined release date for 1.3.0 stable. The developers are working hard to get the trunk version to the stable level.
The situation is the more people we can get into the trunk version to find the bugs, the quicker the bugs can be identified and resolved. If people not upgrade waiting for the stable release the longer it will take to find the bugs. So the best situation is to get as many people as possible into the trunk stream to identify issues faster. This will make the 1.3.0 release come faster too.
Understand when I say bugs, the trunk is not unstable today. There are many updates to fog per week as the code is fine tuned for best performance. So you will need to update your fog code frequently to take advantage of the performance improvements.