GitLab does have the advantage of an excellent, container-based CI... but there's nothing stopping you from using GitHub to host your repositories and GitLab to run your CI if that's what you choose.
Seems that Github also destroyed a database.
Accidents happen. Both companies seems to be open about their issues and are willing to improve. I do not hold it against them.
It could in fact result in a a more stable service, as the developers will start thinking about all the other stuff that may happen.
As qw mentioned, we know of at least one time this happened to Github.
So to use both you’d have to push to both, which doesn’t seem like a hard task to automate.
The CI integration is far better than what github + Travis offer.
Gitlab has been steadily improving and I don't see any lags and slowdowns which used to be a thing in the past.
Not to mention that they are far more open about their platform and don't enforce propriety scripts on you.
Ironically GitHub (the biggest open-source platform) is not.