The aerocharger that boost is good, is it's own breed of turbocharger.
It was designed to have zero lag and nearly no exhaust resistance.
So essentially the engine doesn't even know it's there.
As a result, it does not produce the amount of boost you would get from a traditional turbocharger. A traditional turbocharger robs more energy from the exhaust, but the pay off is more boost.
The theory behind the aerocharger is to deliver what you need when you need. No more, no less. This produces the smooth power curve.
A traditional turbocharger produces more than you need all the time and you use some external mechanism to blow off the excess (wastegate). Your power curve can only be as smooth as your method of expelling the excess is.
A lot of the people I know that use turbo's on cars, don't consider the aerocharger as a "real" turbo, since it does not produce max boost at all stages.
Aerochargers were designed to be efficient devices. Wikipedia goes into greater detail than I can;
http://en.wikipedia.org/wiki/Variable_geometry_turbocharger
I agree the echo cycles bike is a monstrosity. Impressive but bizzare. You get a bit of that with the Rotrex too. It just hangs there on the engine where nothing is supposed to be. The aerocharger, on the other hand, is invisible. People look my bike up and down all the time and never even notice the turbo.