I found "Atlas Shrugged" to be a lesser book. It is of course the second greatest work of modern literature. But The Fountainhead made me shake. I sometimes read during my meals and one day I couldn't even eat my food properly as my hands were shaking too much because of the sheer intensity of the novel. It has not happened before or since.

Also Fountainhead gave me much more laughs than Atlas Shrugged (I have a peculiar sense of humor as I found Sherlock S3 EP1 first 15 mins to be funnier than the entire length of Deadpool.)

Atlas Shrugged was actually started out as a way to explain what Fountainhead was all about in the first place and IMO it showed. It's the single most intense book ever written to my knowledge.