[jitix]

>"But it'll effect my decision to work there. I've interviewed people at my previous job, and they have flat out decided not to join when they were told we weren't using Github and had no plans to move to it."

This is a bit extreme IMO. Tools should be a secondary concern for any developer. If a job is right for a person, such details should not matter.

[eropple]

Those details influence whether the job is right, though. I won't work for a company that uses CVS, for example, because it tells me a lot about the culture of the company. They may have perfectly defensible reasons that make sense to them to use it, but I will, through my own cultural biases and feelings, not be comfortable there.