It's designed to compete with handwriting, not a keyboard. It's designed more for PDAs or for those with disabilities that limit the use of keyboards.
It's kind of hard to explain, so take a look at it here:
http://www.inference.phy.cam.ac.uk/dash
It's open source, and it's a research project, so it's a little bit "interesting" to say the least. But still pretty cool. Although after I used it for a few minutes, I started to get a bit dizzy. Definitely not for everybody, but it's very creative.