Some of my best friends ride diamond bikes. The ones I trust demonstrate that they are, indeed, comfortable in that posture on the saddle. I don't understand it, but it must be true.
The folks I have little patience for (as they have none for me) are the riders who think it HAS to be painful or you aren't 'biking'.
I never tried a Brooks. Tried 100 other things, gel shorts, gel seats, no pads, rock seats, different postures, tucked, upright. My old GT had 53 different hand positions for variety and stress relief. I NEVER got comfortable on the diamond bike. The yellowbike is my wondermachine, and I'm a stickin' to it. Cue the Carlton Heston quote.
And I still fervently profess, no matter what it is -
_________________
ADC - The right bike is the one you will ride.