What I've noticed, and personally experienced, about these porting projects is that they're generally a premature optimization but are a great way to learn a new language. The gains from a port are largely intrinsic in nature, residing with the programmers. However, systems and operations largely carry on just fine with the original language chosen. Only one story comes to mind where a programmer had a legitimate pro…
Writing in a fast compiled language is not premature optimization. Premature optimization would be something that makes the code more complicated and more difficult to follow but produce better performance. Writing the same code in a fast compiled language is just the default thing that you should be doing when you are not doing premature optimization. Writing in a slow interpreted language is more like premature "de…
IME thinking about language performance at all is premature optimization; language performance almost never makes the difference, other between-language differences will swamp any gains from language performance.