[cat199]

Hammer1 is a log-structured snapshottable data filesystem with near-live master:slave replication, similar to e.g. zfs/btrfs, with very low memory requirements.

Hammer2 will, last I checked, enable multi-master clustered volumes plus replicated fanout mirrors and caching clients at the base system level (e.g. not an overlay application like other systems)

While there is a focus on keeping releases as stable as possible and the tip of the source tree stable, it is heavily under development so some amount of low-level expertise is probably a good idea.. which isn't to say you can't use it for day-to-day use.

Systems are used for different things - one being heavily under development doesn't necessarily mean it isn't suitable for some use cases