I downvoted you at first and then changed my mind. I think I would like your comment more if it were more worded like: "buried in here are great examples of important optimizations that did not require a rewrite". Or something like: "this article does a great job of showing that you can hit many reasonable performance targets while using a GC'ed language like Go."

You can pretty much always get better performance with more control over memory, and more importantly, you can dramatically lower overall memory usage and avoid GC pauses, but you have to weigh that against the fact that automated memory management is one of the few programming language features that is basically proven to give a massive developer productivity boost. In my corner of the industry, everyone chooses the GC'ed languages and performance isn't really a major concern most of the time.