I'd love to use Guix (or Nix for that matter) as my day-to-day system but (and correct me, if I'm wrong) the package maintainer story is a bit off putting for me. From what I've understood, packages are maintained in a public git repository (GitHub [0] for Nix and savannah.gnu.org [1] for Guix), which might be great if there are enough people submitting updates, but at least for critical system components there should be clearly defined maintainers to make sure all security patches are applied in time.
Also I'm not sure how I feel about a core part of my potential operating system being hosted by a now Microsoft-owned company. On the other hand GitHub might be more reliable and better fit to server a huge amount of users than savannah...
I actually see the just-a-git-project aspect of the Nix/Guix distribution maintenance a massive win on transparency grounds. I agree that I'd like to see a bit more dedicated "ownership" of key components, but I see that more as a lack of manpower meaning that many people have to spread themselves quite broadly.
But at the same time I'm quite hopeful that this model can produce a maintenance culture that's less territorial, arcane and officious than is my impression of e.g. Debian's methods and processes. As much as I love Debian, of course - but it definitely feels like yesterday's approach.
I also guessed that the lack of dedicated maintainers is due to a lack of volunteers, but that's something that stops me from using either guix or Nix at least from handling the critical part of my OS (kernel and base system).
For development environments and other stuff, both are great tools, but I guess the real power comes when you manage the whole system through any of these managers.
There are tons of dedicated maintainers. You can see that in the maintainers attribute of most packages. So I don't get your point regarding the lack of dedicated maintainers.
I maintain several packages there, and a bot sends me an automated message every time upstream updates the source, and auto-generates a new package definition for me. Things are really streamlined and bleeding edge. The unstable channel is often more up-to-date than Arch Linux even, due to the high number of Nix developers.