I'm guessing this probably says more about those 2 particular models of bikes than anything. I've mostly owned climbing bikes and they've been all over the spectrum regarding rigidity. Not a scientific analysis by any means but, I used to own a certain Belgian-based brand's lightweight/climbing bike that felt like the bottom bracket area/chainstays were made out of wet pasta. My current primary road bike is Canyon's lightweight bike(Ultimate) and it's at the opposite end of the spectrum. The perception at least, is that it feels "fast."