I wrote both the WebDAV client (backend) for rclone and the WebDAV server. This means you can sync to and from WebDAV servers or mount them just fine. You can also expose your filesystem as a WebDAV server (or your S3 bucket or Google Drive etc).

The RFCs for WebDAV are better than those for FTP but there is still an awful lot of not fully specified stuff which servers and clients choose to do differently which leads to lots of workarounds.

The protocol doesn't let you set modification times by default which is important for a sync tool, but popular implementations like owncloud and nextcloud do. Likewise with hashes.

However the protocol is very fast, much faster than SFTP with it's homebrew packetisation as it's based on well optimised web tech, HTTP, TLS etc.