Latest important couple of features are Go To Definition and Back. Move the cursor inside any identifier defined in your project and press F4 to go to the place where your symbol is defined. It might be a class, a field, parameter or a local var of any enclosing closure. Then press Shift+F4 to return to the place you were before. I know, that’s very very useful!
Also, now you can customize the keyboard shortcuts, finally.
See the changelog http://code.google.com/p/minibuilder/source/browse/trunk/AirMiniBuilder/changelog.txt
For installation instructions and other info, check project page