It's only partially open source. They let you smell the freedom, but you can't really have it.
I disagree; you can ignore the proprietary parts just fine.
For how long?
I don't know. So what? No different than a fully open source project that might be abandoned by its core developers. Either we fork or we move to another solution.
EDIT: It's not exactly an uncommon model; e.g. Nginx follows the same.
Complete and utter FUD, this is not the way GitLab operates - more importantly they are from the core an open source and transparent organisation that values both equally.
Yeah Yeah FUD you say... the same company that killed Gitorious.