This new version is a substantially different from the regular updates .Almost all previously existing code has been rewritten, some parts from scratch. These changes were so comprehensive, that new version goes with beta label. Additionally to source improvements, a new beta feature has been added to component.

As you have already noticed, the latests Joomla! 1.5 comes with mootols upgrade plugin, that gives an ability to extend usage of popular javascript framework:

• MochaUI implemented as new user interface.
• Each site template now have represented on separate canvas with all positions on it.
• The positions can be Move and Resize on canvas.
• Save a new layout.
• Smooth canvas selector.

The dragging modules feature is remains same, along with publish and assign to menu. As you can see there is a plenty things to play with. You can download free demo version, but before you do it, notice that beta is limited to all versions of IE. This apply's both to free demo and club versions.