> they've repeatedly rejected suggestions for improving them.

I certainly agree that it's easy to imagine better issue management or patch review than GitHub has today - like many other projects we use other systems. When I've talked with GitHub engineers, all of our issues are well understood and they have plans to address them.

My skepticism is around the strategy of building and supporting our own things vs. partnering with places like GitHub that make a living building and supporting such software. In the Mozilla-specific case, they have proven open to working with us in the past, by pony-trading enhancements to Firefox for enhancements to GitHub, and the inability to deliver has been more on our side :-/