When you copy a file or folder to another, by default Windows shows you a 'time remaining' display along with a progress bar, which isn't very reliable. It may keep showing '5 minutes remaining' for about half an hour, for example. When you have TeraCopy, however, the paste command (or drag n' drop action) spawns a more detailed interface, similar to the one shown below.

As seen in the screenshot above, the transfers can be paused (finally!) and resumed, so as to free up he resources - to launch a big program, for example.
The 'More' button expands the interface into a detailed one, shown here.

If there are errors during the operation, you can retry with a single click. The rest of the copying will continue after successful copying, or after skipping the erroneous file. There is even an option to verify a copy operation by comparing with the original.
Another very useful feature shows up when you are about to replace existing files. Imagine you are trying to merge two folders containing many duplicates scattered in multiple, multi-level sub-folders. In case of the default Windows utility, you'll get a warning when the source and the destination have similarly named folders. If you choose 'Yes', all the duplicate files (meaning, files with identical names) inside the folder will be replaced! What gives?!
With TeraCopy, you will get a prompt with multiple options only when duplicate files are identified. The prompt will show the sizes, names & last-modified dates of both the files, and options to replace only if the file being replaced is older, replace all older files, skip the current file, or skip copying of all duplicates. Very useful when restoring a backup from an archive.
The official website also says,
TeraCopy uses dynamically adjusted buffers to reduce seek times. Asynchronous copy speeds up file transfer between two physical hard drives.As shown in the extended view above, its is also possible to manually specify the buffer size.
TeraCopy is Windows Only. It is a free download ( TeraCopy Homepage )


