Brooks Imperial with 10K + miles on it,
This last year my schedule has forced me into really only riding one day a week, so that's ended up producing one 60+ mile ride a week.
The Brooks do have ridiculously short rails so a setback seatpost may be required to get the fit right. Velo Orange makes a nice one at a relatively reasonable price. If you are siting on the back rail, the position of the saddle and not the break-in may be the problem