So recently it was brought to my attention about a new(ish) filesystem being created. BcacheFS has some really cool features, some for example are

Copy on write (COW) - like zfs or btrfs
Full data and metadata checksumming
Multiple devices
Replication
Erasure coding (not stable)
Caching, data placement
Compression
Encryption
Snapshots
Nocow mode
Reflink
Extended attributes, ACLs, quotas
Scalable - has been tested to 100+ TB, expected to scale far higher 
High performance, low tail latency
Already working and stable, with a small community of users

I learned about BcacheFS as i am currently going through an Gentoo install and wanted to try out a new filesystem. i originally went for ZFS until i learned there is no active maintainer for OpenZFS on Gentoo as of now. and looked at Btrfs and eventually found BcacheFS. The features look very amazing, however i couldnt find many people daily driving it? i saw a few posts on Arch wiki about trying to get it to work. and i try installing it, as my main FileSystem, but ran into trouble when trying to install grub. its exact complaints was something along the lines of "cant install grub on /dev/sdc3 /dev/sdd ". i was trying to make staggered storage with a 500gb SSD and a 2TB HDD. But eventually gave up after watching a few videos of immolo which he eventually got it working but only thought Unified grub with Systemd. which for my Gentoo systems i really prefer openRC. But enough about me, do any of you fellow linux users use BcacheFS? if so whats your setup and experiences?

also if you have recently looked at lore.kernel.org Mr.Torvald says he regrets merging it into the mainline kernel because of bug fixes. https://lore.kernel.org/lkml/CAHk-=wj1Oo9-g-yuwWuHQZU8v=VAsBceWCRLhWxy7_-QnSa1Ng@mail.gmail.com/ which i thought rather interesting