GitHub is used by some development teams across our large organization, including our small web team. It's used as a central code repository for storing our website code and allows multiple developers to work on separate branches simultaneously, then merge those changes into the main branch once their work is finished. It also keeps a history of changes so we can tell who changed things and when they were changed.
Pros
Seamless integration with Git. Although you can use Git without using GitHub, the two have become almost synonymous.
It provides a nice web-based UI for interacting with your central Git repository.
Facilitates working with multiple branches, forks, and pull requests—all different aspects of having multiple people working on the same code simultaneously.
Cons
Honestly, I'm having a hard time coming up with any cons or things I would change.
Likelihood to Recommend
If you use Git and have multiple people working on the same code, then GitHub is for you. If you're a sole developer and don't need to share or publish your code, then you might not have much need for GitHub.