Reviewing an operating system is an odd endeavor, because people don’t really use operating systems; they use applications. The OS should be as transparent as possible, acting as a platform for applications. In today’s cloud-driven world, however, the notion that your application will run in a single OS is tenuous at best. Toss in the increasing use of smart devices, whether phones or tablets, and the idea of a single-platform operating system is less relevant now than it was just a few years ago. These days we have “ecosystems”—Microsoft, Apple, or Google, take your pick.