To start with, the Surface Pro would have the advantage of convertibility. It's a tablet when you need it to be one--and when you snap on one of the keyboard covers, it becomes a laptop that can take full advantage of Windows 8 with a touchscreen designed to interact with Metro apps. You'll also get digital ink support: Pen input can be convenient, and this will be part of Surface Pro, though Microsoft hasn't said yet whether the pen will be an included feature of the base-price model or an extra-cost option. At 10.6 inches, the display will be smaller than most Ultrabooks; for many people, however, the flexible design will justify that tradeoff.

If the Surface Pro isn't intended to compete directly with the iPad, so be it. But what about the Surface RT? How will it stack up against an iPad or Android tablet? Those tablets, like Surface RT, run lower-power, ARM-based processors.

The Surface RT will give you more ports than most competing tablets, along with the ability to view two apps on one screen. The Surface RT tablets will carry at least 32GB of storage (the iPad and many Android tablets start at just 16GB). Though the Surface RT won't have the iPad's high resolution, it will have an optically bonded display, which eliminates the annoying air gap between the screen and the glass for clearer images, improved contrast, and reduced screen glare. Like its more powerful sibling, it will also have a comfortable built-in kickstand. All of those features represent useful improvements on today's tablets.

But Microsoft's Surface RT runs into trouble on other metrics. If its weight turns out to be 1.5 pounds (as currently estimated), it will be just 0.06 pound heavier than the ; but iPad itself got heavier this year, not lighter. Android tablets, by contrast, are consistently moving toward lighter weight; for instance, the Surface RT at 1.5 pounds will be about 0.2 pound heavier than the Toshiba Excite 10.1 or the . Microsoft lists the Surface RT's display as "HD" rather than as "Full HD," which may mean a resolution of just 1366 by 768 pixels—and that won't be competitive with iPad's Retina display, or even with Android tablets like the Asus Transformer Pad 700, announced at CES, and the (both with resolutions of 1920 by 1200 pixels).