Hello there,
I have been using Copyhandler for about two months now and tested it. I am very pleased with this programm and happy to have a nice replacement for the windows copy dialogue :-)
Tho appart from the techical point of view the 'usability' is important to me too and there are some things I do not really like. Even after using it for over two months I still get very confused about the dialogues asking to replace/continue it etc. The german translation I am using is also not exactly how I am used to in other Windows programms, so I edited the translation myself to make it a bit more usability-friendly. I would suggest icons for the buttons and decluttering the window... grouping the buttons a bit more logical and reducing the space between the infos of the file. Seeing the file-icon next to the name would also be a very nice feature, tho not that important. Also I would just show one date as two dates for each file also mess up the window even more.
When copying an already existing file Copyhander creates the file and adds 'already copied' to the name. This behavior is nice, but not where it does put the text

The extension gets messed up when you always show it like I am doing and the file needs manual renaming to be usable again. Adding 'Copy of *.*' and 'Copy(2) of *.*' and so on would be nice.
The last thing I noticed with Copyhandler is that sometiems the Explorer is not updating immidiatly. Ofcourse this is an issue of the explorer, tho CH could send a refresh to the process after a file has been moved - this would make CH more responsive.
Greetings
Michael