Bold opinion. I extensively use GitHub actions and GitLab CI on a daily basis, and I am slowly liking GitHub Actions more. GitLab CI is much more straight forward if you have your own Docker image, but the mix and match approach in GitHub actions, despite the configuration complexity, is more robust in my opinion.

That said, my rudimentary knack is that GitLab CI tend to be quite fast in their free hosted runners. I have CI jobs completing in under a minute on some setups that otherwise take 2-3 minutes on GitHub hosted runners. This could be because I use a custom container image on GitLab, that basically requires no additional tooling setup.