Microsoft’s new version of Windows is fantastic, jarring, and risky at the same time. Fantastic because it marks the clearest sign yet that Microsoft is embracing the future, shifting from the device that defined the company—the personal computer—to the new era of mobile machines. Windows 8, which is being released on Wednesday as an unfinished “consumer preview” (download yours here!), is an excellent touchscreen operating system. A few days ago Microsoft loaned me a prototype Samsung tablet running the new OS, and I’ve found the interface to be just as good as—and in some ways even better than—the iPad’s OS. If hardware companies begin making decent tablets to run Windows 8, the new operating system could make for the first worthy rival to Apple’s unstoppable machine.