OK, so Brad C. asked me to do a little vid to show how audible the noise is that's coming from the Letus motor. The sound is being picked up by the internal mic on my Canon HG10.
I guess the conclusion is that the motor noise can be heard - to some extend. My advice would be to attach an external mic and move it a couple of feet away from the camcorder. That way, the noise from the Letus could be avoided.
Warning: I sound like a dork :D - that's why I always add music :)