[$] Nix alternatives and spinoffs

Since the

disagreements that led to Eelco Dolstra

stepping down from the NixOS
Foundation board, there have been a number of projects forked from or inspired
by

Nix that have stepped up to compete with it. Two months on, some of these
projects are now well-established enough to look at what they have to offer and
how they compare to each other. Overall, users have a number of good options to
choose from, whether they're seeking a compatible replacement for Nix (the
configuration language and package manager) or NixOS (the Linux distribution),
or something that takes the same ideas in a different direction.