The most valuable features are the Git Hooks and SSH keys. The Projects Tab, which shows you the todo list and the progress for projects, is very helpful.
What needs improvement?
I would like to see integration with Slack such that all of the changes made in GitHub are reflected there. You would simply enter the Slack URL and the notifications about code changes would be forwarded.
What's my experience with pricing, setup cost, and licensing?
The private repositories are free, which is very good.
Which solution did I use previously and why did I switch?
We used to use BitBucket, but when Microsoft announced that private repositories would be free on GitHub, we switched.
What other advice do I have?
GitHub is definitely a platform that I recommend people use. I would rate this solution a ten out of ten.