GitHub has integrated issue tracking that make hunting and solving bugs easy. Each project's issues page can be filtered by closed issues, assignees, labels and milestones. Issues are also sortable by age, number of comments and update time.
Any user can fork a project and submit a pull request. If accepted by the owner, the fork will be merged with the master branch. Forking in GitHub also is very easy, it's really just a two-click process.
Due to the fact that it's proprietary and that many external services integrate only with GitHub, it's becoming harder and harder to migrate a project away from it. That will be a big issue the day the company will make controversial choices (like SourceForge)
Other project hosts such as GitHub, BitBucket or GitLab have easy, simplistic UIs that help new and experienced developers alike to browse code right through the browser. LaunchPad on the other hand is very weak at this. Most of the projects have poor (if any) documentation and no way to determine...