When GitHub was bought by Microsoft, Gitlab made moving your repos to them super easy. Apparently not enough people have moved and it would seem even with sustained attacks from all kinds of different vectors, it would seem people continue to stick with them.

I use both Gitlab and Github and have yet to experience any downtime on any of my stuff. I do however, work at a large corporation and the latest NPM bug that hit Github caused enough of a stir where it basically shut down development in all of our lower environments for about two weeks so there's that.

But I do agree, and it seems like their market share increased after the Microsoft acquisition which is contrary to what I heard in all my dev circles because of how uncool MSFT is to many of my friends.

Not really:

GitHub - Historically, GitHub reports uptime around 99.95% or higher, which translates to roughly 20–25 minutes of downtime per month. They have a large infrastructure and redundancy, so outages are rare but can happen during major incidents.

GitLab - GitLab also targets 99.95% uptime for its SaaS offering (GitLab.com). However, GitLab has had slightly more frequent service disruptions compared to GitHub in the past, especially during scaling events or major upgrades. For self-hosted GitLab instances, uptime depends heavily on your own infrastructure.