I would be interested to know how many people out there use these types of libraries, as opposed to ‘raw’ C/C++, Delphi, VB or whatever to code their apps.
Personally, I find Glut, for example, more confusing than it’s worth. But I can imagine that for a complete beginner it does have some merits.
With the Win32 API you have so much more control over your application. In GLUT, you don’t have that much control over whats going on when creating/managing/destroying a window, for example.