I have been on a mission for us to use GIT with our XPages and Notes work for about 10 months now.
And it is just getting to the point where it is coming together nicely although it has been a LOT of hard work.
We still have issues like the previous post but it is working well. The latest step change was integrating our GIT repository ( bitbucket.org ) with JIRA which is the ticket system / agile board that we use.
Referencing a JIRA ticket in the GIT commit messages now shows the specific code changes up in the ticket which makes it a WHOLE lot easier to QA check and also for other developers in the team to get up to speed when looking at recent changes to a customer application.
The scheme we are using is still broadly this one which I will write a bit more about soon.
For any smaller dev shops ( < 10 people ) Atlassian JIRA / Bit Bucket / Tempo Timesheets and JIRA Agile is an amazingly good deal for @$40 a year ( on premises ). Let me know if you have any questions about it. I will do a screen cast some time too.