The latest update to MarcEdit adds an enhancement called "RDA Helper". RDA Helper is an in development tool that provides the ability to "RDA’ize" AACR2 records. It is intended to ease the transition between AACR2 and RDA, especially when working with vendor batch records and legacy data.
The functions of RDA Helper allow users to batch auto process records, adding field data including the 3XX fields. It includes an option to evaluate the 260/264 fields, breaking out copyright dates as appropriate. RDA Helper can also expand abbreviations.
RDA Helper includes an automatic GMD generation function for libraries wanting to continue use of GMDs.
More information and video demonstrating these new functions is available at Terry Reese's MarcEdit page.