The Intel tablet weighs 903 grams and is 13.5mm thick, while the NVIDIA/Windows RT model weighs 676 grams and is 9.3mm thick. They each have a 10.6-inch display. Office Home & Student 2013 RT is listed for the Windows RT tablet, as well as microSD, USB 2.0, and Micro HD Video. Office isn't listed on the Intel tablet, but x86 Windows 8 devices will run all standard Windows applications. Ports on the Intel tablet include microSDXC, USB 3.0, and Mini DisplayPort.
Even with the cover, the tablets are quite thin, as you can see here:
And here:
The newly unveiled Surface site doesn't say which model is shown in those pictures. In fact, Microsoft's site says these "images are design renderings and not photographs," even though Microsoft did show off actual hardware prototypes at its announcement. In any case, the Windows RT version will be available in 32GB and 64GB flavors, and the Windows 8 Pro device will be available with 64GB or 128GB of storage. Each have front- and rear-facing cameras, and 2x2 MIMO WiFi antennas.
Microsoft claims it's a tablet that is as great as a PC and a PC that is as great as a tablet. As for availability, the Windows 8 RT tablet will be ready around the time of Windows 8 general availability, a few months from now. The Windows 8 Pro unit will ship a few months after the Windows RT version. They'll be sold in US-based Microsoft retail stores and online. Microsoft said suggested retail pricing will be competitive to a "comparable ARM tablet or Intel Ultrabook-class PC," but we don't know the exact prices yet.
So far, we're not seeing any indication of integrated 3G or 4G cellular connectivity.