I'd not call the borrow-checker "productivity-consuming" : it is indeed a tough challenge for somebody learning the language, but in the medium/long run it becomes totally transparent when you've internalized its expectations. I've been working in Rust full time for one year now, and the only time I really had to think hard about "how to write this piece of code while complying to the borrowck rules", I was really happy to have it, because I would have written a nasty memory bug if nobody told me that I was doing something stupid.

It comes with a steep learning curve though, and I remember giving up three times in two years when I decided to give Rust a try. It eventually clicked on the fourth attempt(Idk if the docs had evolved between the third or fourth time or if it's the result of the slow progress I made through the three first try) but now, I really happy with the language.