I wrote less than 2 KLOC of Go in my life (at Google, because I needed a web server for an internal dashboard, and Java was too much pain), and one thing is for sure: while I did not like the language per se, I did not hate it either, and I was able to get used to it in about 3 days, which is how long it took me to write the code. I literally knew nothing about it at the outset, and I felt comfortable in it after writing less than 2KLOC. I can't think of another high performance language with such a short learning curve.

I've tried Rust and concluded that it solves problems I don't have. I work mostly in C++ (more like C+, I tend to keep my code pretty simple), and with unique_ptr<>s, shared_ptr<>s and judicious use of concurrency primitives I can avoid pitfalls well enough that I maybe encounter a self inflicted concurrency or memory management issue once every six months, if that. And it pays amazingly well, and there's an enormous number of libraries available. That said, when I need a high performance web server, I'll use Go without hesitation. When performance doesn't matter, Python and Flask are pretty indispensable.