If you are completely unable to get smooth shots without jitter, you are either doing something wrong or you have a defective unit. How are you mounting the unit to your slider carriage and how are you mounting the camera to the second shooter?
I have owned the Second Shooter for a couple of weeks and have worked with it for about 10 hours so far and am mostly happy with it. My main complaint with it is that when I power down the controller, the vertical axis goes into almost a free fall, and if I don't react quickly enough the camera almost crashes into the sider.
This needs to be fixed through firmware update if at all possible.