> The host system and isolated environments will all be managed declaratively and reproducibly using Nix, a purely functional package manager

Nix seems cool, but all of my forays into it have been so unpleasant as to be unworkable. It seems to work well enough if all of your dependencies are already in the Nix store and have been thoroughly tested, but as soon as one has to start writing Nix packages themselves it's a train wreck: the peculiarities of the Nix expression language, the chaos and lack of documentation in nixpkgs, the immense understanding one must have of the common low-level libraries used to create Nix packages, and you'll still spend tons of time trying to package obscure C dependencies with their own bespoke build systems.

My constructive feedback is:

1. Add types to the Nix expression language so someone digging through the code can have some idea about what needs to be passed into various functions. This would probably help people traverse nixpkgs as well, since the client code will need to "import" the types of its arguments.

2. Make Nix more syntactically familiar. Familiarity here seems like it should be more important than innovating on programming language syntax. Thanks for not going full-Haskell on us, but it would be nice if looked more like JavaScript or Python or something that virtually any programmer could look at and recognize (I'm no great fan of either of those languages).

3. Very controversial, but the whole industry needs to minimize the number of C and C++ dependencies. Not only are these languages fundamentally insecure, but projects in these languages have their own bespoke build systems which assume dependencies are already installed at the correct versions and in the correct paths. Packaging these projects is painful, and it's largely the reason we have package maintainers who specialize not in building programs of a certain language, but in building certain dependencies.

It's been amazing for me. Especially when combined with home-manager [1], which provides declarative user environments and flakes [2], which provide a even more declarative and more easily shareable package format.

Getting my exact setup on a new device - including lots of GUI and terminal app customization - takes a single `nixos-rebuild-switch`, and works every time. Everything is configured in a single config file, from hardware and system service setup, over window manager setup, all the way to installed Vim/VS Code/Chrome plugins and lots of application configs.

The ability to easily roll back to previous configurations and boot into old configs from the boot menu in case something breaks is also brilliant.

You can also just install and run pretty much all software on demand, similar to `npx`, without polluting the system. ( nix run some-app). Declarative, reproducible development environments for each project are the cherry on top.

That said, the onboarding experience is horrible. There are A LOT of things to learn, and the documentation is bad. I also agree that the language, while somewhat fine, is not great and very undiscoverable.

The Nix ecosystem is a diamond in the rough. Sadly it would take a lot of effort to simplify everything and make it more polished.

I'm afraid Nix will continue to remain very niche.

[1] https://github.com/nix-community/home-manager [2] https://nixos.wiki/wiki/Flakes