Microsoft's "RichCopy" is a newer (free) alternative to RoboCopy that is meant to be faster.
RichCopy is a great utility; it make it very simple to set up a copy job, including all of the extra features like purging deleted files, excluding certain file types, and only copying files that have changed. It will even show you the corresponding command line for the options you have chosen so it can be easily integrated into a batch file.
The command line to copy only changed files, purging anything that was deleted from the source, would look like this:
richcopy "C:\path\to\Calibre\Library" "e:\Backup\Location" /FSD /P /PF