rclone sync changes the destination to match the source, including deleting destination files when necessary. The official documentation warns that this can cause data loss and recommends a dry run or interactive mode first. Its purpose is mirroring, not automatically preserving every previous version.

rclone copy does not delete destination files merely because they are absent at the source. That makes it a better starting point when extra destination files must stay, but it is not an immutable backup: changed source files may still update corresponding destination files. Define version retention separately.

Both commands operate on a directory’s contents, rather than adding another enclosing directory with the source name. Before a real transfer, use a disposable source and destination, include a file present only at the destination, and inspect the proposed actions with --dry-run. Check the transfer direction and the full paths, not just the command name.

Verdict: rclone fits users comfortable with explicit paths and command-line review. Use sync only when destination mirroring is intended; prefer copy when extra files should remain, and keep a separate recovery copy either way. YNIX reviewed the documentation, not transfer performance or restore reliability, and assigns no test score.