A really nice piece of kit, well packaged and unusually, comes with HDMI and VGA adapters in the box.
In Windows 7, just plug in, Windows installs the drivers on-line and that's it!! Just use the normal screen resolution control to set up the extra display or move it around.
If you are using Visual Studio 2010 or other software which uses hardware acceleration, it is a good idea to disable the hardware acceleration as you can otherwise get "streaking" or persistent areas on the "USB" screen. As a programmer using 3 screens, for me this is an ideal piece of kit and it is infinitely cheaper and a far better solution than playing around with 3-4 head graphics cards (I had a lot of problems with Matrox and NVidia 4 head cards failing/not working), if this is all you need.
Probably wouldn't be much use for gaming on (I don't, so can't comment), but for adding extra screens to a portable or a PC it is just perfect, and far better than StarTech's offerings - with which I had many problems with Windows 7 crashing etc.
Barry