- Facebook does not use Git due to scale issues with their large monorepo, instead opting for Mercurial.
- Mercurial may be a better option for large monorepos, but Git has made improvements to support them better.
- Despite some drawbacks, Git usage remains dominant with 93.87% share, due to familiarity, additional tools, and industry trends.
As far as performance goes, Microsoft did manage to make git work for them later on (…with many contributions upstreamed and homegrown solutions developed—but then, Facebook is the same, isn’t it?).