Doesn't work worth beans
I tried this device at the CES earlier this month. IMHO it isn't anything like ready for primetime. I'm a reasonably fast typer, 60 wpm or so, and I had a difficult time punching out "The quick brown fox jumped over the lazy cow". It was innacurate and unreliable. 60% of the time punching the wrong letter or punching two letters instead of one, sometimes simply not punching anything at all when I hit a key.
The only way I could get even vaguely reasonable results from it was to clasp both hands into a fist with my index finger sticking out and keep the hands well away from the table top, finger poking the keys with a big motion beginning from well off the table top.
Great idea, I'd give it a few more years research before trying that one again, though...