The device seems to be interesting, but keep in mind that theoretically, you can gain only a fraction of a percent in fuel efficiency. Normal combustion is more than 99% complete, so it's hard to see how you can gain 40-50% in fuel efficiency just by changing the constitution of fuel (which in itself is doubtful - changing the structure of fuel requires a lot of energy).
Unless you haven't already tried it, it is very easy to ride carefully and increase mileage considerably. And when you've got such a device attached to your bike, it might be that you unconsciously drive smoother, with resulting decrease in fuel consumption.
I wouldn't put too much belief on this device. You can achieve the same results while riding smoother and properly tuning your bike.
My 2 cents...
P.S. Imran, thanks for the link.