Microsoft currently offering free private repos and them acquiring GitHub may be quite telling. I don't think people fully realize what kind name recognition GitHub has, on the Git hosting space.
When Microsoft shutdown their competing product to GitHub, I think they had like 200 active users. Compare that to GitHub, which had millions of active users. Maybe this is the same with private repos. That is, the number of paying GitHub customers is an order of a magnitude more than free VSTS customers.
I really think Microsoft wants what Amazon has and if they can funnel GitHub users to their cloud service, this acquisition will become a no brainer. Plus, the data that GitHub is able to gather from issue conversations, code reviews, etc. may well prove critical for ML/AI research, that can help Microsoft develop intelligent software tools.
Ok, but VSTS isn't GitHub. GitHub's UX is solidly above its competitors, and I would tend to agree that the primary reason for looking elsewhere is price.
