Interesting question. I had a Brooks B-17 that I absolutely loved out of the box and liked less and less over years of use. I started this trip with it but it became too uncomfortable to continue on.
Since I loved the brand new, unbroken-in B17, I thought a Cambium would be perfect for me. Mid way through this tour I switched... I hate that Cambium with the fire of a thousand suns. I found it really painful to sit on for long distances day after day, and eventually I began getting really bad saddle sores. I have since changed it for some cheap saddle I found in a bike shop and I'm so much happier.
So... my long winded point is, you might be fine with a leather Brooks. I loved my B17 but hated the C17.