I'm proud to announce the first release of StepSync, a file sync tool for GNUstep and MacOS (even for venerable PowerPC).
StepSync allows synchronization of folders, optionally recursively descending in sub-folders. It allows thus various options of performing backups: pure insertion, updates and including full synchronization by importing changes from target to source.
After months of development and testing, I consider it stable enough, I tested it with thousands of files and folders.
You can find it at the GNUstep Application Project. I already have plans for new features!