Windows 8 is definitely a GUI for mobile devices.  However, since I cannot touch a desktop screen and drag icons around with my hand, the productivity that was gained in Windows 7 (as the fix for Vista) has now vanished on my laptop.  I desperately want to reinstall Windows 7, knowing full well that Microsoft Inc. will "persuade" me to stay with Windows 8.

In addition, the Start tiles are vaugely familiar - somewhat like the MAC Launcher (1) from OS 7 (circa 1994). (Dubious that Apple will sue a principal shareholder)

The Launcher - Control Panel (2)

Notwithstanding that Microsoft is being sued by SurfCast (3), there are several enduser design issues that are apparent in this hybrid GUI (aka Windows 8)"

1. hand gestures do not translate to non-touch computer screens
2. START tiles create tunnel vision... akin to linear path based learning
3. No option to return to a previously productive GUI

Typically history repeats itself if you live long enough to see it.  Thus, just as the MAC Launcher was a management function providing a tunnel vision (ATM like) experience to display a "dumbed down" interface, the Microsoft Windows 8 Start will be singluar task focus screen, rather than a multi-tasking desktop.  On the positive side, the tiles can be dynamic and constantly changing, just like a scene out of Harry Potter.

References

(1) http://en.wikipedia.org/wiki/System_7

(2) http://apple.wikia.com/wiki/Launcher

(3) http://einfogames.com/news/surfcast-sues-microsoft-for-infringement-of-tiles-usage/