Hi, I need some help understanding how things work technically mainly. I own a cheap Opteka SV-HD http://www.amazon.com/Opteka-SteadyVid-SV-HD-Stabilizer-Release/dp/B00DRGQETA, even when I find a perfect front-back and right-left balance I'm never able to get a smooth shot no matter how hard I try. Considering the more expensive options like the Glidecam 2000 or ProArm USA AutoPilot that actually look and work the same what exactly do they have cheap stabilizers don't? I mean if it's just a matter of physics once you find the balance what changes on the product that lets actually achieve a smooth shot?