Disclaimer: the last time I used an ISO for installing Guix was before there was a graphical installer, so I'm not sure what it's expected to look like now.
Anyways, I tried booting the latest release on a netbook, it failed around/after KMS. Kernel seemed to lock up. No panic, no usable visible log, not responding to Ctrl-Alt-Del, had to reboot with Sysrq-Alt-b. I added nomodeset to the kernel command line in GRUB and managed to boot it that way, although that still didn't immediately result in a usable terminal, vtty1 only had a non-blinking cursor if I recall correctly. Had to switch to vtty2 or above to do anything useful. So, most users can't be expected to know about nomodeset, so there should be a clearly labeled "safe graphics" mode, just like how some other distros do it. There have been other issues and discussions about generating multiple configs from a single reconfigure, this would be an important and practical use case for that. IMHO the simplest thing is to just let config files return a list of operating-system records and make that into a menu in GRUB. This would also cover the use case of wanting a boot time choice in kernels.
