Its nice being able to go all the way from fully GC reliant cyclic data-types with closures all the way to memory control-freak every byte and microsecond matters by using stack objects and 'var' parameters. Often you can keep 90% of the code and just tweak a few slow points.

Even though Nim by default works with a GC to manage memory, I regularly use Nim to work with direct-memory/raw-pointers and can still have increased memory safety by using HOOKS and ARC. I have written about my experience here[1], in case somebody is curious.

1. https://ramanlabs.in/static/blog/raw_memory_management_patte...

And for the stuff that matters, it is usually possible to tinker around enough to get it pretty much as good as Rust or C++.