We've wanted to make this change for the last 18 months, but needed our Enterprise business to be big enough to enable the free use of GitHub by the rest of the world. I'm happy to say that it's grown dramatically in the last year, and so we're able to make GitHub free for teams that don't need Enterprise features.
We also retained our Team pricing plan for people who need email support (and a couple of other features like code owners).
In general we think that every developer on earth should be able to use GitHub for their work, and so it is great to remove price as a barrier.
I'm a user of both - Github for OSS, and Azure DevOps for private work. IMO, these areas are where they are best suited - pipelines in particular are really powerful in Azure DevOps, and user/permission management, AAD integration and integration with build agents are all excellent.
I really like Azure DevOps, but all this has me worried about it's future - do you know if it's going to continue to exist and be developed in tandem with Github?
0: http://azpodcast.azurewebsites.net/post/Episode-321-GitHub