@xerz @aral I've started writing a post also. I've noodled around with it a bit on Mac and have tried NixOS in a VM.
The ecosystem is quite overwhelming (and a lot of the docs are old or not great).
I'm starting by dipping a toe in and using it as a partial alternative to Homebrew, and using it for development environments and scripts... but the Nix language and Flakes etc. are somewhat mysterious. The learning curve is pretty steep.