I love the S Pro low waist. The wide flat waist band is very comfortable. Of course, everything I wear is low waist, so the thought of anything on my waist makes me itch. I don't think age makes a difference; I'm 57.
I had the SSS shorts many years ago. The S Pros are lower, but I think they were made a bit higher in the front in last year's model, because I have 2 pairs bought in 09 and 2 bought in '10 and they are slightly different.