If you tell me which specific piece of software you tried to package, I can probably explain what is going on. I strongly suspect that it is either not Nix's fault, or an inherent tradeoff in packaging software (i.e.: not a design flaw, but simply a result of the correctness of package expressions being more tightly controlled in Nix than in other languages). The main exception to that statement that I've seen are cases where Nix works fine, but the Nix expression takes so long to build that iterating on it is very difficult. Luckily, there is a solution for that in the pipeline: "recursive Nix", which allows `nix-build` to be called _inside_ a Nix build sandbox, thus allowing safe memoization of things like `gcc`.
