Almost any of the touchscreens you might buy today (especially those offered at more reasonable prices) will have bezels around the edge. By definition, a bezel forms a raised edge around the boundaries of monitor. When you try to slide from beyond the edge of the monitor onto the display surface, there’s a slight gap that is unavoidable as your finger falls off the bezel and onto the display.
Why am I telling you this? Because Windows 8 uses edge-in gestures of all kinds to provoke the charms (slide in from the right), for app-switching (up from the lower left), for split-screen (from the center left), and so on and so forth. On touchscreens with a bezel, “grabbing an edge” so to speak, can be a problem and will negatively impact the user experience (as in “drive you crazy”).
There is, however, an easy fix. For example, if you take a look at the controls in the NVIDIA control panel, you’ll see that it includes an entry labeled “Adjust desktop size and position.” If you’re willing to sacrifice some pixels around the edge of your display, you can easily beat the edge detection issue by moving what Windows 8 sees as the edge of the display inward, far enough away from the physical edge (and bezel) to prevent the finger drop-off issue from hampering the edge detection process.
By fooling around with the settings in the NVIDIA Control Panel widget (AMD/ATI Catalyst offers similar capabilities, and I have to imagine the Intel 2000/3000/4000 controls work likewise), you can move the edges of your display 20 or so pixels in from the absolute edge (I found my 1920×1200 monitor worked nicely at 1900 by 1188, for example) and give Windows 8 some room to detect your finger sliding across the edge boundary past the bezel.
Sure, you’ll lose some display pixels on your monitor that way (and see a small black band all the way around the edge). But gosh, it sure beats struggling to get touch to work properly, or being forced to switch to the mouse to get the UI behaviors you’re after.