@dvd GHC (A Haskell compiler) also has a official self-hosted GitLab EE migrated from Phabricator, and use it to manage the upstream: https://gitlab.haskell.org/, https://mail.haskell.org/pipermail/ghc-devs/2018-December/016613.html.
They are hosting well and I have not heard of any major problems there.
But, gitlab.com may provide more stability than self-hosting.