I like all three of those bikes, but for me, 700x28c tires and low spoke count on the two Jamis's portend a rough day if you ever want to tour. The tires are a big part of the shock dampening aspect for the rider, and beefier tires and wheels are usually chosen. They look like good commuters though. Therefore my choice would be the KHS of the three.
I would like to see something like the KHS (steel frame-700x35c tires, flat bar) in a disc brake setup. That would just about be ideal for me. I don't know where it can be found.