My important takeaway from this one:
Upon reflection, he realized that he was being sold on the wrong set of virtues: purity above all, repeatability, and rollbacks. What he really values most in Nix, however, is:
- building without deploying,
- atomic builds,
- source-first approach with proper binary caching,
- building new releases as soon as they are available,
- switching customers to new versions quickly, and
- enjoying a much faster build time.
I guess the last one is mainly in comparison to their previous gentoo-based solution, and the first one is when compared to Puppet, but it is very interesting to note that the value preposition of Nix changes depending on what sort of tool you view it as.