I've never ridden a leather saddle but I figured I might give one a try.
A couple of things:
How do they respond to vibrations? Lacking any padding/cushioning I could imagine perhaps they're harsh, or perhaps the 'hammock' principle means you're somewhat isolated from buzz through being suspended?
The Brooks 'S' series is supposedly for women but apparently the only difference is length and width measurements. With a shorter nose they're significantly lighter, so I'm figuring I'd prefer an S model for that reason. Unless I've missed something and there's some other differences?