FWIW…
http://derrickoswald.blogspot.com/2013/02/quick-rebuttal.html
The open loop versus closed loop thing is pretty interesting. The reason 2D printers got cheap is because they replaced open loop stepper motors with closed loop dc motors. They also, paradoxically, got more accurate. Happened in hard drives as well, and many other places.
That could well be the next revolution.