yea I know they're made from more expensive alloy. And I will interject and say that cost/benefit is a matter of opinion. I've never ridden ultegra or 105, but something tells me I'm not going to notice the difference, unless I'm doing time trials or riding cross country. I don't really care about smooth shifting or 3 pound differences. If the bike can get from point A to point B and allow me to enjoy the ride, then it's good enough for me.

What I would like to know more is how do these more expensive alloys compare with lower end components. As far as I know, durability and light weight are the only factors weighing in.