I think both Nix and Guix are great and ready for prime time. Everyone should test one at least

The initial installation is a standard 'next,next,next', and the result is apparently similar to a Debian installation

Nix support more packages natively, but guix also supports nix packages

It gives me a lot of peace having all my system defined in one file. Very easy to rollback or re-generate in another drive. Not really important if the root gets corrupted or misconfigured