Although Guix reads better than Nix (after all, it's Lisp), I found the support and resources available for learning severely lacking.

Plus, you have to jump through hoops to install non-free software, which goes against the ethos of Guix anyway.

IMHO, Nix is clearly "the winner" here and we'll see more and more adoption as it improves. Lots of folks are doing exciting work (see https://determinate.systems/, https://devenv.sh/, https://flakehub.com/). And the scale and organization around nixpkgs is damn impressive.