This Heinlein novel, published in 1956, is one of the better ones I have read. I'm not the only one who thinks so; this is one of the books that earned a Hugo Award. It is one of his earlier novels, but not one of the ones sold as 'juvenile fiction', so it may have escaped some editing as a result.
I like the first-person narration style, and how it reveals the character's view of the world. It does a good job of actually making the political and social content part of the plot. It avoids going into too many technical details, with the result that it has aged better than many stories of the time period.
The only real howlers, from a scientific point of view, are the existence of Martians and the assumption that a human could walk around on Mars with nothing more than an oxygen mask. But this book was written nine years before the Mariner 4 probe flew past Mars and collected the first close-range data on the place. The situations presented in the book were perfectly plausible, given the scientific data of the time. It is easy to forget how much we have learned about the universe in the past several decades.
Overall, I would say that this is my second or third favorite Heinlein book, behind 'Starship Troopers' and about tied with 'The Moon is a Harsh Mistress'.