Microsoft is right on this one. The term "App Store" is very generic (although most people here won't admit it).
As for Apple saying "Windows" is generic, the only operating system that has a more generic name is "Operating System 10"
But I doubt that Microsoft is the only company that thinks that the term "App Store" is to generic, Apple will probably lose because Microsoft is a much bigger company with many more resources that they can use to their advantage.
As for Apple saying "Windows" is generic, the only operating system that has a more generic name is "Operating System 10"
But I doubt that Microsoft is the only company that thinks that the term "App Store" is to generic, Apple will probably lose because Microsoft is a much bigger company with many more resources that they can use to their advantage.