The different sound of scanners is caused by automatic blanking point optimization in Moncha. As every automatic thing, it is good, but it's not always perfect. Maybe the sound is because of blankig lines - Moncha doesn't put any blank points on these lines. But we've developed this optimization for several reasons:
1. I always hated to draw picture to every single blanking point. It took too much time.
2. When I finished drawing some image for one laser and I wanted to project the show on another one, I had to go through all blanking points and add more, because the image was not correctly displayed on this second laser.
Now in Moncha you just set correctly 4 sliders and all(!) the frames are looking good(maybe not perfect) on your laser.
And another issue - I haven't seen any destroyed scanners by Moncha(or Fiesta) software. But I have destroyed some scanners using another software. And this is thanks to automatic scanrate adjustment - Moncha doesn't allow to run the scanners faster than it is neccessary.