I love ZFS snapshots, but I don't recommend them for large files (in my case, storing any manipulating ISOs of old hard drives). Snapshotting made reclaiming disk space difficult because snapshots would keep space reserved for files no longer visible.
However, I still love ZFS snapshots for other use cases. For example, it's great for making server backups (both in case of server software malfunction and disk failure).
Just my two cents.