Gitlab has the benefit of having very little traffic, both free and paid. Their limits are still way above the current usage so less likely to be an issue
Worth mentioning GitLab's paid enterprise offering are more expensive than GitHub's, on a per-seat basis.
Lots of companies moved because it was cheap, but it's not anymore. Ironic that companies might choose to migrate to them now for stability, rather than price.
GitLab has its own problems. It might be somewhat more available than GitHub lately, but it too is not immune to incidents, particularly involving workflow dispatch and managed runner availability.
Plus the UX isn’t nearly as good. Sometimes it feels downright clunky in comparison.
