Guix System uses Linux as its kernel, so no driver "is GNU", whatever that means.
The choice to use the Shepherd rather than systemd is motivated by a vision that we can get better integration using a single language and set of tools all the way down. As an example, this gave us services in containers several years ago:
Overall Guix System alone gives a coherent and unified view of the system; systemd also does that to some extent, but it's not in as good a position as Guix's declarative OS configuration to do that. For example, this is the kind of system exploration that Guix enables:
