There are three big differences between these handy touch screens and a PC’s screen: angle, distance and time interval.
The screen of a phone or tablet is generally more or less horizontal. The screen of a desktop (or a laptop on a desk), however, is more or less vertical.
via Why Touch Screens Will Not Take Over: Scientific American.
My belief is that touch screens make sense on mobile computers but not on stationary ones. Microsoft is making a gigantic bet that I’m wrong.
From: Windows 8 — Disappointing Usability for Both Novice and Power Users
With the recent launch of Windows 8 and the Surface tablets, Microsoft has reversed its user interface strategy. From a traditional Gates-driven GUI style that emphasized powerful commands to the point of featuritis, Microsoft has gone soft and now smothers usability with big colorful tiles while hiding needed features.