I read about these a year ago or so when the concept was new. The interesting thing is the method used to measure the keystrokes made, not the laser keyboard image. It basically uses infrared lights and timing (the time it takes for the light to bounce back) to get a 3D "map" of the immediate surroundings. This has a high enough refresh rate to capture the keystrokes of people typing. The applications for this can go FAR beyond a keyboard that isn't there. One example might be airbags that can judge where the person is and how tall they are so that the car can pop it out at the height and distance that is most safe and effective.
Anyhow, I would definitely like to try the keyboard. Lack of tactile feedback might be a problem, but I'm sure most people can adjust. It would be very useful to be able to have a PDA with this built in, plus a small popout stand device. Basically, you'd pull out (or pop out) the balancing piece, stand the PDA, and turn on it's built in laser keyboard. No extra items to carry around. Cell phones could do this too. If anyone here has tried one, please reply to this.