Well, we have had multi-pane, er, dual screen environments on both macs and pcs for nearly 20 years. Arguably, the innovation is having the pains behave like an input devices (keyboard on one, touch screen on the other) as well as output. If this device can be marketed at pricing comparable to others, it should be a hit.
I predict that Kyocera's Echo will be the first of many multi-pane devices to come. The multi-pane user interface is overrunning multi-windows on smartphone and touchscreen tablets--even Windows and MacOS are rumored to be readying multi-pane modes. On the iPad multi-panes are managed by double-clicking to bring up a film-strip showing icons for each pane that you can switch between. On multiple devices you manage multi-panes by running the same app on each device. For instance, when I watch MLB.com on my PC, I run the MLB At Bat app on my iPad to watch a tactical animation of each pitch. The I open the same app on my iPod Touch to keep track of the other games.