While he probably dramatized it a bit much, Tom Wolfe's book was extremely well researched and a heck of a lot more accurate than the movie version. In particular, the movie version made it seem as if Chuck Yeager's flight of the NF-104A (where he had to eject) was a joyride where they basically didn't question him taking off because he was in charge. In reality it was a carefully planned, and he had full authorization to attempt it with a large crew working on the preparation.
I enjoyed both the book and the movie very much. Saw the movie several times in the theatre in '83/84. Have read the book probably at least five times. Wolfe was an incredible writer. I've read several of his other books, and they've all been a good read.
However, my big beef with both the book and the movie was how they depicted Gus Grissom as having messed up, causing the hatch of Liberty Bell 7 to blow, and leading to the capsule sinking.
That story fit Wolfe's narrative (the chapter was called "The Unscrewable Pooch") but is not supported by the facts. Whenever the hatch was triggered manually, the backlash bruised the astronaut's hand badly. Grissom's hand was not injured. Grissom always denied blowing the hatch, either deliberately or accidentally.
Grissom was pretty much vindicated long afterward - Liberty Bell 7 was recovered in July 1999, and the edge of the hatch was slightly deformed. It's likely that the hatch was damaged on splashdown, and blew spontaneously. Unfortunately, the hatch door itself was not recovered.
It would have been good for Wolfe to have revised the book at that point. And at the least, the movie could have pointed out, in the epilogue, that Grissom had flown a perfect Gemini 3 flight in 1965.
More recently, just in the last few months, footage has been released which appears to indicated an electrical discharge from the recovery helicopter to the capsule, followed immediately by the hatch blowing.
So why did Wolfe make Grissom a scapegoat? It appears Wolfe relied heavily on two sources - Chuck Yeager, and Pete Conrad. Did either or both of them have an axe to grind? They're all gone now, so we won't ever know.
John Glenn claimed in his autobiography that he felt that the movie had really hurt his chances politically - he had wanted to be the Dem presidential candidate in '84. He thought the movie depicted the Mercury 7 as a bunch of buffoons, and said they should have called it "Laurel and Hardy go into space".
In reality, the Mercury 7, besides all being accomplished test pilots, also all had post-secondary degrees, typically in aeronautical engineering. Their IQs ranged from 135 to 147. (Average IQ is defined as 100, with a standard deviation of 15. 68% of the population has an IQ between 85 and 115. 16% have an IQ greater than 115. Only 2% have an IQ of 130 or greater.) Therefore, all of the Mercury astronauts were in the top 2% of the population for intelligence, and at least one of them was a genius.
The Mercury astronauts were far more intelligent than depicted in the movie.
As well, Jack Ridley, Yeager's Beeman-chewing sidekick in the movie, was in reality an absolutely brilliant aeronautical engineer.
OK, rant over ... these points aside, I still loved both the book and the movie.