now that 6.18 is the new LTS kernel, will I have a good experience with bcachefs if I stay on that LTS kernel instead of tracking newer stable kernel versions?

I currently run NixOS with ZFS-on-root, and because ZFS is also out-of-tree, the "stable" ZFS version in nixpkgs isn't always compatible with the most recent stable kernel. to keep things simple I tend to just stick with the LTS kernels.

previously when I've tried to experiment with bcachefs on NixOS I ran into a catch-22 where I needed to upgrade to a newer kernel to get bcachefs support but doing so wouldn't be compatible with ZFS.

yeah, we'll be supporting 6.18 ongoing.