The Patreon page has a very good overview: https://www.patreon.com/bcachefs https://www.patreon.com/bcachefs TL;DR: it's based on a stable, pre-existing design

The Patreon page has a very good overview: https://www.patreon.com/bcachefs https://www.patreon.com/bcachefs TL;DR: it's based on a stable, pre-existing design (bcache) to avoid design bloat and ensure stability, it's much faster than the competition with similar feature sets (e.g. far lower latency than btrfs), it's very small and lean, and is extensible enough to support most of the common needs (COW, multi-device, replication, compression, encryption, etc etc). Also, bcachefs will hopefully land upstream in Linux and stay there, and unfortunately it seems ZFS will forever have to stay out of tree at this rate (of course, many distros make ZFS very easy to use these days, so if you're comfortable with it, just use that!) I donated to the project and have been tracking it. I'm not sure how long it will take until Kent sends a request to pull in the code to the upstream kernel, but it's been progressing nicely lately.