The Surface Pro version (with Intel x86 processor) is a very promising refinement of the Windows tablet PC concept, and a strong contender in the MacBook Air/ultrabook category. I am glad to see Microsoft, with both this and Windows Phone, embracing the advantages of tight integration of hardware and software design. I can see a Surface Pro with docking station as the only computer many people need.
However, the size, weight, ultrabook level pricing of around $1000+, and initial lack of much touch-friendly software all put the Surface Pro in a different category than most of the iPad market. So the big question for me is whether the ARM-based WindowsRT version of the Surface, running only newly written or ported software, not any existing software for Windows 7 or earlier, can develop enough software and accessory support to be viable in the "pad" or "slate" category pioneered by the iPad, as opposed to the "tablet computer" category created by Microsoft a decade ago. Microsoft's goal seems to be that from now on, most Windows software will be written in a way that works with the input device being either only a touch-screen or only a keyboard and trackpad/mouse: let us see how that plays out.
P. S. I just realized that the forthcoming Windows Phone 8 changes to using the same NT kernel for its OS as Windows RT and Windows 8 Pro, and adds support for some progrsmming tools previously available only for regular Windows but not Windows Phone 7. Maybe that will lead to more touch-oriented apps being cross-developed for both Windows phone and Windows pad/tablet devices, and give MS more chance of catching up on mobile app selection. The momentum of using iPhone apps and developers being able to easily adapt them to take advantage of the extra iPad screen space helped to get the iPad market going.