Version 2013.06.02 means Experimentor Workbench now includes custom objects and custom object types!  This is really helpful, because you can create your own objects with your own custom properties:

Of course you can have collections of your own objects as well; the documentation has several examples of how this can be useful.

Run statement updates

Additionally – although a lot more minor – you can now use expressions with the run statement, rather than just an ID.  This allows you to do things such as the “more complex example” on the run statement‘s documentation page, such as: