A lot of what is related to comfort also has to do with proper fit. And fit certainly depends on your riding style and your anatomy. Having been a shop rat for 15 years, this is a question I’ve heard since day one. In most instances, the best thing you can do is choose a saddle based on your riding position, skill level, fitness and general anatomy and “break the saddle in to your butt”, not vice versa.
However, materials do make a difference. Brooks are comfortable once broken in because they conform to your body over time. There used to be some saddles out there that used surgical gel in place of standard bike saddle gel. I rode those for a while for commuting, and was very pleased with the comfort and support.
My preference has changed a bit. Selle Italia Flite Ti, was once my top choice, but I’ve since found the Arione to be my saddle of choice.