Jim wrote:
Hello there,

I was reading the Trek Web site, and found the 520 comes with bar-end
shifters.
What benefits do the Shimano Dura-Ace bar-end shifters offer, compared
with
modern integrated shifters?

In addition to the answers others have given, I'll add:

I can't stand having anything on my bike that I can't take apart and
repair with relative ease. There should be a difference between a bike
and a Swiss watch.

- Frank Krygowski