I heard the hype. Figured I would give it a try. Installed emacs with nix Install spacemacs on top of new emacs. Throws odd errors. Uninstall emacs with nix

Install emacs with brew Install spacemacs on top of emacs It works!

To pull users from brew it needs to work at least as well, especially for common tools like emacs. Go check out the number of issues related just to emacs installs, it is kind of amazing.