As it was said, the RD does move but it is very subtle. You won't see it swinging back and forth. I never rode the biopace rings but the main advantage for me with the q rings was the smoothness of the pedal stroke, especially while climbing. Now when climbing my pedal stroke seems a lot smoother as the dead spot has been greatly reduced or even eliminated. Also I found myself riding 1-2 cogs smaller since I was not wasting power in the dead spot. If you really want to feel the difference between round and the q rings ride with the large q ring and a small round ring. This is how I tested it. Your legs will tell a difference in the way you pedal as soon as you shift. First few pedal strokes fell "odd" and then your legs adjust. Shifting can be set up to work just as well as with round rings. All I had to do was slightly raise my FD but the majority of adjustments is done by properly angling the FD. It shifts perfectly with my SRAM Force FD. Many had luck with Shimano FD as well. Its just a bit of a PITA to get the adjustment right. In the end I was sold and purchased the small ring and plan to use them for good. After wheels this was the best upgrade for me.