First off everyone is different. I rode the Fizik Arione for a year of pure misery and the Alliante for six months of almost as much misery.
Brooks B-17 is a good saddle but for a racing position and a new light weight bike it is just plain clunky. Rode one for ten years of touring back in the seventies.
The Brook Swift and Swallow look great on a racing bike and are comfortable, but the leather is too thin. I had a Swift for 2 years and the second year I had to constantly adjust it tighter due to streatch and sag. I am six foot and 175-180 and that may have been part of the problem. Had to throw it away after 2 years. An expensive mistake.
Brooks Pro- saddle perfection. I had been riding the Specialized Romin for a couple of years but developed severe pain under my right hip bone ( same side as a hip replacement via a posterior approach- this was likely the cause of the pain and not any inherent design flaw of the Specialized). Out of no other options I bought a new Brooks Pro and I kid you not, my very first ride on this rock hard new saddle was completely pain free. And the comfort just keeps getting better.
Couple of myths. The break in is much less than some allege. My saddle was great from day one and keeps getting better if that makes any sense.
Rain is not an issue. I ride rain, snow, salt, mud and just care for it as suggested by the company. I do not even bother with the plastic cover.
This saddle is like a living thing, it gets better and looks better with age. Same goes for the leather bar tape.

PS, my ride is a Merlin Lunaris CF/ TI bike with an aggressive set up and significant saddle to handle bar drop.