Annoyingly both fail at basic stuff like falling back the graphics card, something Debian had solved 10 years ago, no configs needed, no matter Intel/NVIDIA/AMD. Even without the correct driver or firmware falling back to VESA or fbdev should be a given. Never had so many black screens as now. Even Windows has done better job at giving you a basic resolution while you install the drivers
Or maybe it's just the state of the Linux ecosystem, with the introduction of Wayland and NVIDIA open drivers, causing regressions
Also the unintuitive inverse of traditional package management, where if you want to update one package, all the system updates by default
Which increases the amount of bugs, having frequent updates to a stable system
To make it better you can add 2 channels, and call them nixos-stable v24 nixos-latest v25, keeping most of the system one version down increases stability a lot
Of course the incorporated Grub boot build choices is great to revert back to a working system
I really like the the separation Guix makes on having close source being a concern of a separate project
But both of them are equally easy to install open source only or include proprietary