FreeFileSync is described by its author as
…is an Open-Source folder comparison and synchronization tool. It is optimized for highest performance and usability without restricted or overloaded UI interfaces
FreeFileSync has a simple yet attractive, with well made icons, interface that synchronizes folders and compares files and folders. The options to compare are based on file size and date and also the file contents. The help button to the right of the big rectangular compare button attempts to explain how the comparison is calculated in both the aforementioned possibilities or features.
The synchronization feature is more detailed and includes the possibility to copy files between folders so that they are identical or to copy files and overwriting any that already exist in the other folder or to even delete files that already exist in the other folder.
FreeFileSync is also capable of saving configurations to be loaded to make future uses even more automated. Batch files can also be saved to ease work for every use with identical folders. Files can also be filtered so that certain file types are not included in the syncing procedures. FreeFileSync is available both for Windows and Linux machines.