For me, I really want to get into niri, but the lack of XWayland support scares me (I know there’s solutions, but I don’t understand them yet).
Also, I stopped using Emacs (even though I love its design and philosophy with my whole heart) because it’s very slow, even as a daemon.
Honestly, the only btrfs feature that interests me is the snapshotting, as the current state of my backups is rather sub-par. There’s just a lot of inertia involved in adopting it when ext4 Just Works™. Maybe next time I install a new system I’ll give it a shot.
As for zsh, I rather like the general “intelligence” I see on others’ machines: the way it autocorrects typos, draws a navigable menu for tab completions complete with colour highlighting… it looks lovely. I’ve been a Bash user for 25 years though, and muscle memory like smashing the tab key to get what I want is a hard habit to break.