I agree, I believe the figure was 50% loss due to heat on compression. However, I disagree with electric motorcycles as being better. It's expensive, 10k starting for Brammo products. If you run out of power, you're fucked. If you run out of power at home, you gotta wait 4 hours to get going again and there isn't a charging infrastructure in Vancouver if you run out of power at work or something.
However... this technology is very very appealing to the public:
Firstly, it is cheap. Air motors are downright the cheapest form of drive (except for spring energy). Even cheaper than electric motors.
Secondly, charging a battery takes a long time. So theoretically, an air powered bike refueled by inexpensive compressors at gas stations means that you have nearly unlimited range in the city. And hell, this infrastructure ALREADY exists!
Thirdly, it's light so if you DO run out of juice, just peddle to the nearest Air station.