Some Free Software projects have already moved to Github, some probably plan it and the Python project will move soon. I have not followed the reasons for why the Python project is moving but there is a long list of reasons to move to a platform like github.com. They seem to have a good uptime, offer checkouts through ssh, git, http (good for corporate firewalls) and a subversion interface, they have integrated wiki and ticket management, the fork feature allows an upstream to discover what is being done to the software, the pull requests and the integration with third party providers is great. The last item allows many nice things, specially integrating with a ton of Continuous Integration tools (Travis, Semaphore, Circle, who knows).

Not everything is great though. As a Free Software project one might decide that using proprietary javascript to develop and interact with a Free Software project is not acceptable, one might want to control the repository yourself and then people look for alternatives. At the Osmocom project we are using cgit, mailinglists, patchwork, trac, host our own jenkins and then mirror some of our repositories to github.com for easy access. Another is to find a platform like Github but that is Free and a lot of people look or point to gitlab.com.

From a freedom point of view I think Gitlab is a lot worse than Github. They try to create the illusion that this is a Free Software alternative to Github.com, they offer to host your project but if you want to have the same features for self hosting you will notice that you fell for their marketing. Their website prominently states “Runs GitLab Enterprise” Edition. If you have a look at the feature comparison between the “Community Edition” (the Free Software project) and their open core additions (Enterprise edition) you will notice that many of the extra features are essential.

So when deciding putting your project on github.com or gitlab.com the question is not between proprietary and Free Software but essentially between proprietary and proprietary and as such there is no difference.