well put Staehpj, especially about spending time with a seat for a while (making slight adjustments etc along the way).

I guess the thing that I most enjoy about the Brooks compared to the other bike seats I've had is the easy movement of my behind as I pedal (no matter what sort of pants, shorts, bike shorts etc I have on)

I could relate it to double layer socks, or wearing a thin pair of socks under another pair when hiking, to reduce friction on your skin as you walk. Thats what I noticed right away with the Brooks. As you pedal, your bum moves, but the leather allows a sort of "frictionless" easy motion of ones bottom, so especially after it forms to your specific sitbones, and then distributes the weight around nicely. I really noticed a reduction in "friction" on my skin. Also, as others often state, it does seem also to breathe a bit more than other seats, so it seems to be less sweaty--or in any case, even when sweaty, it comes back to the "less friction" thing compared to my other seats.

as you say though, so many factors come into play--bar height, how people pedal (sitting up more vs more forward) , how hard or steady people pedal (distributing weight between legs, bum and hands), how fit people are and how much riding experience they have--that more along the lines of being more aware of how to make seat adjustments, bike short choices, underwear choices (not having big seams right under "there")

cheers