I have been using GitHub for about seven years and have been a member since 2011.* I love it and consider it one of the most important tools in my web development arsenal. I also insist that anyone working with me or for me post their code in a repository there. If you’ve ever had to suffer with Subversion or Visual SourceSafe then you know how wonderful git is.
This Wired article is from 2012, but it’s still worth a few minutes of your time if you have any interest in source code management.
Lord of the Files: How GitHub Tamed Free Software (And More)
* Unfortunately the vast majority of my repositories are private and contain non-open source code. Sorry.