Counterpoint: we've moved to GitLab internally (from SVN, granted), and while GitHub would have been easier because it's far more widely supported in tooling and integrations, GitLab has been great for us so far.
I would have preferred to switch to GitHub if we had an internal hosted GitHub Enterprise kind of situation, but so far Gitlab is doing fine for us.
It could be a matter of scale, though; perhaps for larger teams, larger repositories, or pre-existing Git-based MR/CI workflows, it's a dumpster fire, but that's not us so we can't speak to it.
Who knows though, maybe in a few years I'll regret writing this comment.
I would have preferred to switch to GitHub if we had an internal hosted GitHub Enterprise kind of situation, but so far Gitlab is doing fine for us.
It could be a matter of scale, though; perhaps for larger teams, larger repositories, or pre-existing Git-based MR/CI workflows, it's a dumpster fire, but that's not us so we can't speak to it.
Who knows though, maybe in a few years I'll regret writing this comment.