PureSync is a Windows program to synchronize files and folders, and to do backups automatically in the background. Developed by Jumping Bytes/Christoph Güntner
License: Free Personal
Unison is a file-synchronization tool for OSX, Unix, and Windows. It allows two replicas of a collection of files and directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to the other. Developed by Benjamin C. Pierce
License: Open Source
Unison is ideal for users needing real-time file synchronization and strong version control across different platforms, while PureSync excels in backup capabilities and user-friendly scheduling options. PureSync is better suited for users who prioritize backup and mobile access, while Unison focuses on efficient synchronization and advanced features.