Update 2021: the below may not apply to APFS volumes.
On Macintosh, Syncovery can create 100% identical, bootable copies of system volumes. To achieve this, it now copies all the specialty items of the Macintosh file systems. In particular, it copies Extended Attributes, hard links, BSD flags, ACLs, Finder Info for folders, and other items.
To compare existing backups in terms of these special items, use the following checkmarks on the tab sheet Comparison->More: Compare Attributes, With Extended Attributes, Compare Permissions, With ACLs, Enforce Hard Links.
The program must be “Run as root” to achieve 100% identical copies.
Syncovery passes the enhanced “Backup Bouncer” test
Syncovery passes the enhanced “Backup Bouncer” test by Nathanial Gray and Mike Bombich when “running as root”.