Thanks for asking, I’m happy to explain.
The situation with USB graphics support on OS X is evolving, so please do not expect performance similar to that on Windows. Also, be advised that various features (some screen savers, most anything using Quartz including Keynote and CoverFlow) will not work well, if at all, on USB attached displays.
That said, I use our USB graphics devices with a Mac Air everyday, and the additional display space is a HUGE benefit for productivity when I’m just replying to questions like this and doing other basic tasks. I also get acceptable results streaming videos.
The current 1.8 driver has been fairly stable, however a few sporadic but frustrating issues persist.
DisplayLink is working on a new 2.0 driver, and has resolved one of the most frustrating issues on the 1.8 version already in this early build. I currently run this driver with both a UGA-2K-A and a USB3-HDMI-DVI running 20 and 21" external displays from my air, and have a general impression that there are a few issues on the USB 3 display that I don’t have on the USB 2 display.
Adventurous users can read more details and download the driver on DisplayLink’s forum here: http://www.displaylink.com/support/ma…
I hope this helps!