robocopy E:\HQvideo U:\HQvideo_BU /S
robocopy E:\3Dmovies U:\3Dmovies_BU /S
robocopy E:\vrstuff U:\vrstuff_BU /S
When you use either one of two options:
/PURGE : Delete dest files/folders that no longer exist in source.
/MIR : MIRror a directory tree - equivalent to /PURGE plus all subfolders (/E)