For the most part I would confirm everyone elses experience but would add some personal incite.
1. A well worn brooks performs like a different seat altogether
2. Because Brooks seats seem to have a sweet spot for being perfect, they do not lend themselves to alternate positions. On an Ideale 92 I can perch at the nose for aggresive climbs or slide over the back for more streamlined descents. In my experience, the 3 brooks that I have owned were designed for one purpose and if you had the right bottom, they were really good at it.
3. Nowadays there are plenty of seats that are comfortable out of the box, even though some purists say a seat must mold to fit you. You wouldn't buy tires that perform like garbage for a few hundred miles before they "get accustomed" to your roads.