MS is not particularly developer friendly.
...
In fairness, many of the Linux kernel API's change with each new release. But at least the code is open and you can see what's and why. Much more dev friendly.
As a professional software engineer I have to profoundly disagree.
If you write to a specification, and can't look at the source code, you have a much better chance of writing an application that will work on the next version and the version after that than if you have to poke around the source code (at considerably more expense than just reading the API spec) to see what the API does because the documentation is crap or non-existent.