I am successfully using document property promotion and demotion in a current project. There is a document library where the properties are used to fill out a templated Word document. This is using Sharepoint 2010.
I have a requirement to take a single document property that stores a string that contains tabular data and the format really doesn't matter. Then I have to fill out a word table using that document property. Basically, we are using other properties to fill in simple labels (mailing, data, etc) but we want to use properties to fill out Word tables.