I guess I should also say that if you primarily tour in big, wide open, relatively flat areas, it probably doesn't matter very much. Even in the Rockies where the hills (mountains) are long but not steep and are pretty consistant in slope, you don't need to shift often and only need to stand on the pedals to stretch your legs.

But here in Kentucky and our surrounding states, we have very little flat ground, lots of short steep, twisty, no shoulder hills. Makes a big difference here.