It's not just geometry, too, there's also the style of the carbon. I know that the Amira is designed to be SUPER stiff, so that every single twitch you make gets translated into forward motion. Think of a how a super-tight-suspension sports car goes over a speed bump and you have an idea of the difference in comfort on the road.
I have a carbon Crux that is the stiffest thing I have ever ridden in my life. It's fast and nimble and aggressive and all those wonderful racing adjectives, but it is NOT comfortable. I personally would not ride more than an hour on it.
My Ruby is perfect for centuries. "Plush" is not quite the right word, but that'd be my bike of choice when I'm out to enjoy the views and smell the roses. My husband, on the other hand, is quite flexible and loves the aggressive geometries; he has no problem doing Deathride on an over-built Tarmac (Amira) with deep dish rims and somehow doesn't get blown off the side of the road and never complains a word.
So, it's back to your decision on what you want. 
-- gnat!
Windsor: 2010 S-Works Ruby
Pantysgawn: 2011 S-Works Stumpjumper 29er
Whiz!: 2013 S-Works Crux (Singlespeed)
Boucheron: 2009 S-Works Tricross
Haloumi: 2013 Tern P7i
Kraft: 2009 Singlecross
Gouda: 2005 Electra Betty
Roquefort: 1974 Stella SX-73