Sure, and bit for bit reproducible builds are useful in their own right, but what Nix provides is (effectively) reproducible environments. I used to be a huge

Sure, and bit for bit reproducible builds are useful in their own right, but what Nix provides is (effectively) reproducible environments. I used to be a huge fan of Arch as well, but NixOS has significantly boosted my productivity over the last 8 years or so due to the simple fact that my system state is fully declarative and read-only. I never have to stop what I'm doing to fix an unexpected change or broken update. Worst case I roll back and solve it later so I can continue working. It may also be important to point out that while Nix cannot guarantee reproducibility at the bit level on its own (and no single make-style build tool could) it gives you probably the best build environment conceived to date for eliminating environmental sources of non-deterministic build behavior so you can narrow it down to specific build tools, dependencies, etc Also worth mentioning that there is a growing contingent in the Nix community actively working on increasing the number of truly reproducible builds in nixpkgs at a steady rate. Once content addressed derivations become stable, that will be a really nice property for independently verifying the integrity of packages