I was pleasantly surprised to see support for Nim as a task language! very cool! Particularly considering your target market of developers with corporate education budgets, I expected a much smaller set of mainstream languages.
Nim tried regions based memory management and ended up going a different direction. The feature still exists, but the core devs ended up considering it a bit of a dead end: https://forum.nim-lang.org/t/6930
As I said in another comment, the familiar python like syntax, while having the potential for much better performance.
Many data scientists are familiar with Python. They can write similar code and will run much faster by default (or with very little tweaking).
Then, if that's not fast enough, The language is positioned such that you can optimize the code to a much higher degree than you can with Python.
I'm not saying that Python code can't be optimized, but there is a limit to the speed of python code even with optimization. At some point you have to drop down to a C extension (what Numpy, Pandas, etc... does) and then you are just writing glue code in Python to drive the C. You could also use one of the Python optimized compilers, but that has limits and edge cases as well. There is "developer friction" there.
In Nim you can just have the whole program in one language. The program can be optimized to the same level as optimized C code with no special tools. This is much less friction.
What's missing is the libraries. But that will come with time.
The major features are: Python like syntax, Lisp like macro system, potential for C like performance (YMMV of course).
This is my person opinion here:
Nim is part of the "new generation of system programming languages" from the last decade or so. Some other examples in this category include Zig, D lang, Go lang, Swift, Rust, etc...
The whole idea is to provide "modern high level" language features and ergonomics while still producing efficient low level code.
For Pythonistas, The familiar syntax is attractive to Python programmers looking for a more performant language (data science is a prime example.)
Nim is also attractive to lispers looking to move to a more traditional Algol or C like language while still keeping much of power and flexibility that they are used to from macros.
I would say gc:arc beta quality. Very usable for many programs, but needs more battle hardening. Please try it and send bug reports if you find them! That's how we improve!
As others have said, Nim has plugabble garbage collectors, some are quite advanced.
In addition there is active work on a swift like reference counting, lifetime based memory management option. This will be suitable for hard real-time use cases.