Saddle comfort is achieved through the following:

1) Your "sit bones" are directly supported by the wide part of the saddle. It's necessary to know how far apart your sit bones are, something easily determined by sitting on something soft with your knees drawn up, and measuring the distance between the deepest parts of the depressions you leave behind.

2) The front part of the saddle is sufficiently narrow that you don't actually force yourself onto the nose of the saddle through the motion of your thighs pushing against the wide part of the saddle.

3) No padding that can compress your soft tissues, especially in the perineal area. For many people the opposite -- a hole or slot in the saddle where it would contact the perineum -- is helpful.

4) Careful leveling of the saddle. For most people, dead level is the optimal position. Changes from level should be made in very tiny increments. Saddles tilted radically forward or backward almaost always indicate that there is a seriious problem with the fit of the bike.

4) Careful positioning of the saddle. Obviously, if the reach to the bars is too far, you'll tend to move forward onto the nose of the saddle. You should move the saddle forward on the rails. A saddle that's too low encourages the rider to sit on the back edge of the saddle.

Wearing clothing that retains moisture and has seams that chafe can also sometimes cause problems that are then mistakenly attributed to the saddle.

I wouldn't worry much about rail material, but I wouldn't pay extra for exotic metal, either. I've ridden many thousands of miles on SI's manganese rails without problems; I weigh about 210.

RichC