I've never ridden a leather brooks but I can say that I found the c17 cambium to be uncomfortable. My partner switched from a b17 to some generic looking Bontrager saddle and said she hasn't felt as good on the bike in a long time but hasn't done any long rides with yet, but has been on the trainer all winter which I find to be harder on the bum than riding outdoors. I switched to a specialized toupe and found it more pleasant. I use a 143mm but am going to go with a 155mm if I can find a used to see if it's more comfortable... the ass-o-meter at a local LBS put me in the middle of that range.