What is your experience with Nix-Darwin?

I’ve been using it for a few months now soon after getting a Mac Mini, following the instructions to set it up was a bit rocky but fortunately users were helpful, the configuration itself is well done like NixOS itself, but I’ve found it to be very unreliable because often when trying to rebuild, this or that package would failed to build. I feel like its a big flaw of Nix itself, where it shouldn’t let go of previous versions of packages unless they can build successfully, but that’s a whole di...