This excellent Linux distribution has the honour of not needing to recommend a clean install. It deserves to be far more popular. I've run it since 2014 with so few problems, that I can't really claim to "know" Linux anymore.
I still can’t quite figure out why it’s not more popular... then again, I don’t use it either, sadly, because it’s not as popular as I feel it deserves; I feel like there must be some reason it’s not used more, so in turn haven’t dedicated the time to learn it. Perhaps that’s cyclic...
IMO the biggest blocker is documentation. The best way to figure out how to do something is typically to search around in the nixpkgs/NixOS options for what you're trying to do, then go read the code.
There's very little in the way of "here's a common task that new users want to do and here's the blessed way to do it." Even something that should be Nix's MAJOR selling point, like "create a single repo that configures a bunch of machines, including some NixOS and some other OS" doesn't have a recommended way to do it.
Another challenge with the docs is the fact that Nix is
* An OS * A package manager * A way to manage dev environments
A lot of times I find someone who solves my problem but they solve it in the context of building a dev environment and I want to do it in the context of setting up an OS package. It means that even with all the good tutorials and blog posts out there, you might still have a bunch of work to do to get things to work how you want. This translates into tons & tons of opportunities for users to give up.
Also, for some reason, so many examples are done in the imperative manner, and it's not always super clear how to translate them to a declarative setup. Again, just defeating the strengths of Nix and clouding the benefits. If a new user sees a bunch of examples that involve starting nix-shell and installing some dependencies it's both hard to understand the benefits and hard to translate that to a declarative setup.
NixOps[0]? But yeah, it isn't featured as prominently anymore as it used to be...