What's the "Network effect" for private repos?
I also make heavy use of GitHub's issues/milestones system, even on private repos, to keep myself organized. I'd probably use GitLab a lot more if I knew of an easy way to port issues and milestones over to GitHub when I decide to make a project public.
On a related note, can anyone recommend some good external issue tracking systems that integrates well with both GitLab and GitHub?