Nix Flakes are stable enough to replace nix-shell and lets you pin versions, so it has a significant reliability advantage.

Things get a bit tricker when flakes are paired with home-manager and especially nix-darwin, as the error handling leaves a lot to be desired (opaque errors that are extremely difficult to debug, leaving you with few choices outside of nuking all nix and re-starting).

I've been really careful to avoid OS-wide environment management with Nix, as we're on macOS; the only thing I do is `nix-env install direnv` imperatively during our setup script so we can sidestep the need for `nix-shell`.

I'm using nix with home-manager on macOS and I'm very satisfied. Haven't touched flakes yet tho.

If you’re using something like niv, you’ve got most of what flakes will bring to the table. I’m in the same boat as you, don’t want to have people enable any experimental feature to get the dev environment going. I use flakes for all my personal stuff though, just because it’s easier than adding the niv dependency and because it comes along with using the new command line interface. I also like that flakes let you specify multiple targets in a single file.

Would you consider writing up a tutorial? Or is there any resources you'd recommend?

We're midway through transitioning engineers to it, as well as building stuff on top of it to make for a really great DX. I'll probably write a blog post when the whole env is a little more complete.