Microsoft is becoming the defacto leader in open source.
The Language Server Protocol has revolutionized IDEs in general.
And now that they own GitHub (and their projects like Atom), it seems like the entire FOSS developer workflow is likely to be from MS-derived projects. Which I'm sure they are hoping will translate into more cloud service revenue and online software subscriptions.
If you are starting a new company, BizSpark is a really attractive offering. Could run a whole business on it, and yet none of your devs need to be running windows on their machines.