A long time ago I was a Windows developer. I developed for user mode, kernel mode, win32 stuff, etc. And having a MSDN subscription was a must-have. Not only because Visual Studio was included, but also because you were able to download “debug” builds of the whole Operating System; and also you had access to all the Microsoft products in different localizations.
The MSDN subscription was expensive, but it was worth it.
But nowadays, since you can get the Windows Phone SDK for free, perhaps the MSDN is no longer needed.
I’m currently using a MSDN Pro subscription (thanks MS for the gift). And so far, the only feature that I’m using from the MSDN is Visual Studio 2013 Pro. I’ll let you know if I happen to use more features from the MSDN.
RETRO.MOE 