I often hear people say that, aside from proper fit, frame quality is the most important factor in a bike. Why? If a no-name brand, cheap frame weighs approximately the same and has the same measurements, what makes the other one worth the $1,000+ extra? It's not meant to be a combative question, I just really would like to understand. I have a cheapo triathlon frame and (now that I have more money) have wondered whether it would make sense to hang its ultegra components on a "better" frame.