Issue tracking

Faster, more polished, better than gitlab. Just less hassle; gitlab tends to be bloated and slow. While some offer other reasons for their objections, most who prefer gitlab to github are so because gitlab is mostly open-source. I don't see that as an inherent plus; github works fine.

Very easy to use

Free for up to 10 users and Open Source projects, integrates with other Jetbrains products like TeamCity.