http://www.engadget.com/2011/06/01/microsoft-unveils-windows-8-tablet-prototypes/
So, the breakdown:
1. Microsoft decided to NOT do a separate OS for tablets (a bad decision IMO, more on that in a minute). They are actively looking to combine Windows Phone and desktop into a unified OS.
2. The new UI does not appear togglable, but rather "swipe-able".
3. "We're aiming to keep new Windows builds coming every two the three years."
4. Thumb-based keyboard on a tablet. Smarts IMO.
Anyway, my two cents:
Combining tablet and desktop is a BAD move. I've thought this from the beginning when they first started announcing it. In general having your desktop version on ARM chips is going to cause issues. People expect to be able to run their old software on Windows, but that isn't going to happen on ARM-based copies since the programs aren't compiled against the ARM architecture (exceptions obviously for things running under Java). Can't wait to see the people who say "this svcks" after getting an ARM-based Windows tablet and can't use any of their old software. Here's to hoping no ARM-based Windows desktops come out.
Beyond that combining the two will undeniably lead to a massive increase in general bloat of the OS. There's a ton of Windows desktop stuff that makes no sense on a tablet and vice-versa.
Not being able to toggle the UI makes me see the possibility of people accidentally switching between the two UIs as a very real and very frustrating possibility
2 years between Windows releases is going to be a nightmare from both a consumer and developer standpoint. Uhg.
Once again, though, happy to see it shipping with a thumb-based keyboard. [Default] Tablet screen keyboards all svck still.