Hi Antonio, we are working on OSX native so we can leverage the best of the platform and make it really fast and optimized. The first public preview will be for Mac. However Project Comet is architected in a way that will let us bring it on Windows as well and we are committed to it.
I see too much hysterism around this, whether for bad or good. Let me help you guys calm down:
Its OS X native, and no one knows if there's gonna be a Windows release at this point. But I highly doubt it, given that they've built it from scratch and around the OSX engine.