If you're using any version of Windows, one of the biggest problems, even today is the slow speed of copying files. I experience this just a few days back when trying to clean up my external hard disk on Windows 8.1.
Anybody who uses a USB drive be it a pen drive or a hard disk knows how painful it can be when you run into the stupid "USB drive is in use" error everytime you try to eject the same. In such a situation, I normally rely on Unlocker to do the needful. However, that isn't always solve the problem at one go.
The problem with CDs and DVDs is that over a period of time they get scratched or just deteriorate and you end up with lost data. Sadly, hard disks also have this amazing ability of developing bad sectors and before you know it you can't get back data. So, what can Unstoppable Copier do?
Keeping your files safe is one worrisome issue. I have multiple backups of my files, both on an external hard disk as well as on two online file backup services. When you have a few hundred megabytes to backup, you can just replace the folder time and time again.