I run a company that uses Nix for everything.

We're running GitHub Actions. It's good. All the real logic is in Nix, and we mostly use our own runners. The rest of the UI that GitHub Actions provides is very nice.

We previously used a CI vendor which specialised in building Nix projects. We wanted to like it, but it was really clunky. GitHub Actions was a significant quality of life improvement for us.

None of my colleagues have died. GitHub Actions is not killing my engineering team at any rate.