>>27
Shepherd is missing smf patterns for service management (shepherd comm) module provides some of this, there's an important difference from up and ready. It is also missing a clean way to do atomic state transitions, I don't know of anything that does atomic state transitions without making it painful.
completely independent
It implements the same package deployment paradigm, and in fact it reuses some of its code.
Guix looks better than I remember it now thought I checked a month ago but I suck massive cocks, haven't used it in years but it's still not "completely independent" of nix, there's shared code.
The Hurd still needs drivers
The hurd l4 project and a driver unikernel. An old problem was that hurd was mach, not sure about hurd's l4 virtual layer and if it's capable of using a unikernel for drivers yet. I didn't use hurd l4 but hurd mach, still think it's comfier than the linux kernel with the limited drivers.