Conclusion: A Special Solution For Special Cases
Anyone hoping to use this USB 2.0 adapter as a full-fledged second or third display will be disappointed: the bandwidth provided by the USB interface is only sufficient for 2D applications in Windows. Although playing back video at reduced color depths is possible, don't expect any miracles here either. On the other hand, thumbnail formats such as those found on the Internet don't pose a problem. Also, in case you hadn't already guessed, a USB 2.0 adapter is completely unsuited for gaming, as it couldn't push the high frame rates required by modern games. Finally, the lack of a WHQL certified driver is also a possible shortcoming.
An application that this adapter would be more at home with would be displaying an Outlook window or Photoshop's famous tool palettes. In this case, the USB bandwidth is easily sufficient, and the 16 bit color mode limitation is irrelevant.
In the same vein, the adapter is also an interesting choice for notebook users whose only other option for connecting a third display would be using a PC-Card adapter (such as the expensive VillageTronic VTBook) or a PCI breakout box (like the even more expensive Magma CardBus Interface).
Administrators will also find this adapter handy, as it can be used with servers or blades. The VGA connectors on these devices are often situated on the back of the case where they are hard to reach. However, these systems usually sport two USB 2.0 ports on the front, making the USB VGA adapter an ideal administration tool!
If you're looking for a way to expand your desktop space on a standard PC though, we would recommend choosing an additional PCI card instead. Just make sure it is compatible with your existing graphics hardware. Suitable graphics cards can be found starting at $30 and provide smooth displays that aren't held back by any bandwidth limitations.