I overall like GitLab for startups, especially since I can do my own flavor of Kanban with the scoped labels feature of their Premium account. So I'm leaning towards also moving my personal open source to gitlab.com, just to simplify. I would've already moved, but gitlab.com's CloudFlare setup is blocking my Firefox. And a couple times now GitLab has changed the pricing dramatically, and I won't like surprises like that after I've invested many hours to move there.
And there's the mess when people are driven by email notifications for Git repo changes/events that they then access in a Web UI. It's great for wasting people's time, and people also end up with piles of Git repo emails that they casually archive/delete, potentially missing things, due to DRY violation and because there's more steps between looking at the email and going to the Web UI to handle things.
But when you just want random people to be able to log into a Web site and interact with whatever computer-mediated workflow there, telling people to use old-school email is maybe counterproductive.