There are three key ingredients to making an Android system work. You need the right interface to control the system with, the right version of Android installed and enough power to get it running properly.
The ViewSonic VSD220 Smart Display performs respectably on all fronts. With a two-point multi-touch optical touchscreen, you can perform the two-fingered gestures that have become a key part of any modern touch-operated system. The most obvious is the pinch-to-zoom gesture, used throughout Android.
The version of Android used here is Ice Cream Sandwich 4.0, with just a few slight alterations. ViewSonic's main change is the OSD overlay, giving input and screen controls. Other than that, Android here behaves just as it would in a 10-inch Android tablet.
Impressively, the Android UI doesn't feel as if it has been unnaturally crammed into the ViewSonic VSD220 Smart Display, thanks to its core scalability. Unlike iOS, which tends to look odd when blown up to this size, Android Ice Cream Sandwich looks and feels relatively at home on a 21.5-inch screen.
However, there is the core issue that using the ViewSonic VSD220 Smart Display as you would a tablet feels quite laborious. There's a lot of moving your hand from one side of the screen to another, and next to the small movements demanded by phones and tablets, the arm-waving required here feels like an awful lot of effort. And we're not just saying that because we're interminably lazy.
The screen is coated with toughened glass, but its surface is higher-friction than that of most tablets and smartphones, which doesn't help either.
Escape from the Android UI by loading up an app and the situation often improves - a session of Angry Birds Star Wars on the ViewSonic VSD220 Smart Display is just as fun as you'd hope. Although the CPU used here is not powerful compared even to budget tablets like the Google Nexus 7, the dual-core 1GHz OMAP 4430 is powerful enough to make most popular Android games run at full speed.
Many of the most graphically intensive games - first person shooters, for example - are not at all suited to being played on such a large touchscreen anyway.
There are jerky moments in day-to-day navigation of the Android interface, though, and they make us wish ViewSonic had equipped the Smart Display with Android 4.1 Jelly Bean, which significantly greased the cogs of the system.
What's arguably more important is that ViewSonic has packed-in the majority of Google's own apps. The Google Play app store is here, as are Gmail, Google Earth, Google Maps, Google Talk and others. The only significant omission from the Android staples is Google Navigation, which would be pretty useless in a GPS-less device anyway.
The inclusion of these services is a sign that this is a good-quality device. Getting these services on-board requires full Google certification, which is expensive and therefore often avoided by makers of lower-cost Android gadgets. We did encounter a few bugs, though, especially when exploring the Google Play app store. Some patience is required.
The Android UI lets you turn the ViewSonic VSD220 Smart Display into a hundred different things, though. It can be a Netflix portal, an internet radio, an easy Microsoft Office workstation, a web browser, a hugely over-specced weather station and plenty more besides.