It is difficult to answer your question without knowing your purposes and goals. What aspects do you think would make a quality version control host? For me,

It is difficult to answer your question without knowing your purposes and goals. What aspects do you think would make a quality version control host? For me, the primary issue is size. A large number of people use Github. This means that social features like networks of forks of repositories and pull requests are substantially more compelling. This also means that many related websites (bug trackers, project managers) have Github integration. Further, it makes much more sense to design custom desktop apps for Github because it is what everyone uses. Lastly, the more people are familiar with Github, the easier it becomes to suggest it for a project or to contribute to a random Github-based project. The APIs, UI, and general flow of Github are competently designed, but I do not think these are necessarily the core of its success. (I do believe these parts of Github, however, to be better than the competition.) Ultimately, Github is in a unique position because of its (and git's) popularity. Social features that would not work on other sites work on Github. I am sure that the developers and designers of, e.g., BitBucket and Google Code are smart people, but without users they feel a little like ghost towns. This is odd, because I had thought of VCS hosting as very much a commodity before Github.