GitHub has a "network" tab under "Graphs" that might provide what you're looking for.
But when people say that GitHub has better UI, they're more talking about the clean menus and intuitive UI. Some of it might just be getting used to one design over another. Although, BitBucket to me has always felt too cluttered.
Yeah, much less. As the sibling says, GitLab has integrated CI/CD, extensive code review functionality (which GitHub just added), more fine-grained rules about who can merge what where, an integrated Docker hub, etc.
But when people say that GitHub has better UI, they're more talking about the clean menus and intuitive UI. Some of it might just be getting used to one design over another. Although, BitBucket to me has always felt too cluttered.