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
Resilio Sync is a commercial solution that focuses on high-speed file synchronization using P2P technology, making it suitable for larger files and complex setups. Unison, being an open-source tool, offers robust two-way syncing with effective conflict resolution, catering to users who prefer a free and customizable option.