On stage at CES today, Jonney Shih proclaimed his company's new Transformer the world's first 4-in-1 device. By that he meant that it's a Windows laptop and tablet as well as an Android laptop and tablet. This new 13.3-inch slate transforms both physically and virtually thanks to the company's new dual-OS setup. A quick switch of three or four seconds is all that's required to morph you from the Windows 8 environment into the familiar Android UI and vice versa.

The Transformer Book Duet is powered by Intel's Haswell CPU, up to the Core i7 models, and comes with storage starting at 64GB, but extending beyond a terabyte if you're willing to pay the price. The larger storage options will be housed within the keyboard dock, which also expands the device's connectivity options with extra ports.

The Full HD IPS display is crisp and bright, though be forewarned that it's only available on Duet models starting from $699 and up. The cheapest $599 option steps this down to a 1366 x 768 resolution. Physically, the Duet has a familiar feel for Asus products, bringing the concentric circles design on the back — no cameras to speak of other than a front-facing webcam — and a generally solid build quality. It's quite hefty, particularly with the keyboard attached, making it bulkier than most ultrabooks, but then Asus would argue that you have to compromise somewhere when cramming in so much versatility.

My immediate impression of the Duet is that it would have made more sense as a 10- or 11-inch device, primarily because Android already struggles to fully capitalize on the real estate on screens of that size — moving all the way beyond 13 inches just doesn't make sense with Google's OS. It's a different story for Windows, of course, but then you might as well just buy a regular ultrabook. To Asus' credit, it has executed well on the task it set out to achieve, and the new device looks solidly built while living up to the promised near-instant OS switching. The only question is, just how useful will it be in practice?

The Asus Transformer Book Duet will be available in the United States from the end of March, starting at $599.