We use Perforce. Github is great when just using your Source Files, but you need to put your Binaries somewhere else. But regardless, if you use Perforce or Github, both add a certain complexity to your project. Is no one in your project that has some experience in it, who can maintain Repositories or Depot/Workspaces?
If you need help with Perforce, I am happy to help to get you going to understand some of the concept. Just write me a PM and we can have a intro.