Thanks for the link! I definitely agree with the author, NixOS is the only system that does The Right Thing but I cannot recommend it to anyone. I mean, I technically have recommended it to one person, but he's an ex-Arch user so... does it really count? :D
There are definitely still many rough edges and sharp corners!
For software developers and sysadmins with certain temperaments, though, I think it's definitely already a good fit. A lot of NixOS people come from Arch and Gentoo, and it works well for them— although Arch folks who are deeply aligned with its keep-it-simple philosophy are probably usually turned off by Nix.
