In 2011, Google introduced Android 4.0 "Ice Cream Sandwich," which took some of the design direction it had begun on tablets and moved it to phones. In the intervening two years, we've only seen "point" updates for the platform: some subtle refinements and a few big new features, but never a big 5.0 update. Google sees it as a “mature” operating system — it doesn’t have to reinvent the design or the core features, it just has to make them run faster, better, and prettier. With Android 4.4 "KitKat," that trend continues, but this time around the refinements add up to something more — but not how you might expect.

Google always introduces a new version of Android alongside a new Nexus device — this time it's on the excellent Nexus 5. But where we used to think of the Nexus as simply the device that offers the purest, least skinned version of Android, the Nexus 5 offers a vision of Android that includes more of Google's entire ecosystem than ever before. KitKat may have the most visual polish of any version of Android, but the most important features are unique to the Nexus 5 and uniquely Google.

KitKat is Android's biggest step yet into what Google believes is the future of mobile: ambient information, tied tightly to the company's intelligent cloud services, available on cheap and powerful devices. It's an ambitious plan for the future, but what is it like to use today?