Is it really worth dropping over a thousand dollars on a high-end groupset when a well-maintained mid-range setup can provide nearly identical performance, or are we just being suckered into buying a name and some flashy packaging? Whats the real-world difference between Shimanos top-tier Dura-Ace and their more affordable 105 groupset, and at what point does the law of diminishing returns start to apply? Can someone explain to me why I should spend an extra $800 on a set of Dura-Ace shifters when the 105 ones work just as well for me?