I figured this is where most of the Brooks people hang out so I thought I'd post some info about my experience so far with a B17 Champion Special British Racing Green.
Out of the box it was rock hard of course. The first couple hundred miles left me with some sitting bone soreness but not bad. Then the leather began to soften, and soften, and soften, and became more and more hammock-like over time. Not a trace of dimples even after 3000 miles. The leather just sags. I've read some people saying that they like the sag but I can't believe that's how it's supposed to be. It lowers and moves forward your position and puts more pressure on the middle soft tissue and less on your sit bones.
So I tensioned it up a bit after maybe 1500 miles and that reduced the sag, but the sag returned. I tensioned it again a couple days ago about 2 full rotations which helped and produced a noticeably more comfortable ride. It's still not as firm as I'm sure it should be. I expect to have to repeat the tighten, sag, tighten routine until the leather breaks, which probably won't be long.
The saddle came on the bike my LBS built up for me and they initially applied what I assumed was proofide, though now I'm beginning to wonder. I've applied light amounts of proofide to the top maybe 3 times over the last year since I got it.
I've noticed when searching for other people's experiences that a number of people have also written about their Brooks sagging and not moulding to their shape. Does Brooks have a quality control issue?