Well guys you may think this is a joke, but I was working in a company that was giving support in Israel to 300 forigners that gathered in the Holy Land and rode for charity. At some stage I was called together with the main mechanic "urgently" to help a girl that the Campy Veloce rear derailer came apart. We had no veloce with us and believe it or not we instaled a simple 1$ Shimano SIS all metal mountain bicycle derailer replace the Veloce. Guess what? The Veloce ergo-shifter worked as smoothly with the 1$ SIS all metal derailer as with the Veloce derailer.And guess what else? you need a hammer to destroy a 1$Shimano SIS all metal derailer ! If you do not believe this story, try to do it and you will be surprised.
Conclusion: even the most simple components will work as precise as the thousand $$$$$ components.