Some imports work. The ones that failed are those with release notes (which were also the more important ones). And they fail silently (succeeded but no releases imported), which is annoying. I could dig up the issue numbers.
I'm generally very pleased with GitLab. I'm delighted that it's open source.
Glad to hear; I'd really like to see us improve some of our import capabilities at GitLab. We've created a separate team specific to importers and have started moving much more quickly here. Thanks for your patience.
I did this for the first time 2 days ago on two medium-size GH repos and it while was crazy slow, it eventually completed after about 8 hours or so. The actual bits seemed to finish in a relatively quick amount of time, but the project landing page continually showed "import in progress" for all those 8 hours.
Git is simple to import, but all other related data may be subject to API rate limits.
I've opened an issue with some improvements suggestions, like surfacing when we are rate limited and allowing gradual access to the data while the import is going on: https://gitlab.com/gitlab-org/gitlab-ce/issues/66525
