[soraminazuki]

Feature-wise, there's no fundamental difference. All of it boils down to a matter of taste.

But in terms of support, I must say Nix is currently ahead of Guix. It has a large quantity of packages that surpasses any other distros[1], (almost) all of which goes through review. It also has support for non-Linux platforms, namely macOS and BSDs. The community is large and active, and there are various avenues which you can reach out for help.

So if you're interested in either but don't know which to choose, I'd recommend Nix. If you're feeling adventurous and also like Scheme, Guix would be the way to go.

[1]: https://repology.org/repositories/graphs