I've been using Copy Handler for about 10-12 years now.
The one feature that I would like to see the most are overwrite/ignore options
For example, when a duplicate file is being overwritten, ask if I want to overwrite/ignore the destination file with the source file if...
Source is bigger
Source is newer
etc
That is planned to be implemented and is filed under: https://dev.copyhandler.com/browse/CH-17
Be patient - it will be implemented eventually :)