OpsCenter will be much more than NOM/VBR - it will end up being a primary management interface interface for NetBackup related functions.  For example, the Java interface will be EOL'd starting with NBU 8 (this is documented in the 7.0 release notes).  So between now and the release of NBU 8, we'll see a lot of new functionality being added to OpsCenter.

OpsCenter today does not have full feature compatability with VBR although I heard it's coming soon.  I didn't pay attention to the details as we use Aptare StorageConsole, not VBR.

One thing that's not clearly documented is that although OpsCenter is supported on Linux/Unix platforms, Symantec is strongly advising customers to use it on Windows 2008 64-bit system.  Sybase apparently really sucks on Linux/Unix as the database gets large - this isn't a problem for EMM where the database is typically fairly small but is a real problem for OpsCenter where you can have millions of rows in your DB.