Brooks.
For me I don't think its width exactly but shape of the
top of the saddle. The difference to me is the Brooks has a
relatively flat top while the racing type saddles are curved
Ok, this is a stretch, but think of these as saddles on their
side, open side the bottom of saddle ] Brooks vs ) other saddles.
The curve puts pressure on soft tissue in center (top of arc) of
saddle.
I have flites, concors, regals, trans am and none of them are
as comfortable as the brooks.

Marty