I tried for a couple of months, and gave up. I switched back to GitHub for a couple of reasons.
- After some time, GitHub's CI became a thing, it became good enough for me (and other features improved, too).
- Companies want to see your GitHub profile. Publishing your work on GitLab is not going to get you the same exposure as publishing on GitHub.
- Open-source contributors are on GitHub. The majority is not going to create a GitLab account just to fix a bug or open an issue in my little library. If you want community, it's on GitHub.
- Hosting open-source really didn't seem to be a priority for GitLab, so if they don't seem to care, why should I?
- GitLab's quality started to decrease. More bloat (both in terms of UI and code size), slower and slower app whereas GitHub hit the sweet spot of keeping things simple while providing essential features that are fast.