The concept behind Air Display is cool -- use your iPad as a small extension to your Mac's display. For example, let's say that you're working on a project and you want to use your entire screen, but you'd also like to be able to check your email in Mail.app. You fire up Air Display on your iPad, move the Mail window to your iPad, and now you have a small portable workspace that's not interrupting what you're doing on your Mac.
Apps like this are nothing new; just before iPad launch day, Shape Services released iDisplay ($4.99) which does the same thing. However, reviews of that app have been poor and it's pricey for what it does. Our very own Erica Sadun noted another solution in a post about a week later. Her post mentioned ScreenRecycler ($29.90), which uses a second computer (Windows, Mac, etc...) as an additional monitor for your Mac.
The iPad and Mac need to be on the same Wi-Fi network for Air Display to work, naturally. The app and companion System Preference on the Mac (below) work so well together that I had no issues watching YouTube videos that were playing on the Mac on my little "side screen." They looked great on the iPad, although it was disconcerting to hear the sound coming out of the Mac.
One really great feature of Air Display is that not only is it an additional screen for your Mac, but it also adds a second input device to your Mac. I was able to use my finger on the iPad to call up incoming email that was appearing on my virtual screen. I didn't find the accuracy of finger input to be very good in this pre-release version, though, and ended up resorting to a Pogo Stylus for better input accuracy.
There were a few bugs in Air Display, which isn't surprising considering that it's still in beta. When I first started streaming a virtual Mac screen to my iPad, I noticed that the connection kept dropping. A look at the AirPort status in the iPad status bar indicated that the Wi-Fi signal strength had dropped to about one bar, much less than the five bars I see on my network. I rebooted the iPad and everything worked fine after that.
There were also some interesting screen artifacts that sometimes showed up while using Air Display. Once again, they didn't keep me from using the second display, but they just looked a bit odd. Avatron spokesman Elliot Chase mentioned that the artifacting issue and dropped connection issues have been resolved in preparation for release.
Avatron hopes to submit Air Display to Apple for approval next week, with an expected price of US$9.99.