The first thing that I should clear up is that I actually think that "Atlas Shrugged" is a philosophical science-fiction novel. It's set in a future where capitalism has been supplanted by Rand's version of socialism, the economy of America is slowly dying, and all of the great minds of industry and commerce are vanishing.
I should like this novel, because I am interested in the type of novel this book attempts to be. I'm interested in science fiction, and I'm interested in philosophy. Both together usually work for me. But this novel fails in so many regards that I cannot enjoy it at all.
Firstly, since this is a SF challenge, and I am claiming it to be an SF novel, I should consider this aspect first. Simply put, "Atlas Shrugged" is not a good SF novel at all. Although there are some new technologies, such as Reardon Metal or the instrument used for Project X, much of the technology, and the thinking behind it, is firmly set in what would be available to use in 1957. As for the society depicted, you can only be interested in what is happening if you buy into Rand's philosophy, and I don't.
And that leads quite nicely to a discussion about the philosophy in the book. As a philosophical vehicle, Rand's novel fails. Yes, the book expresses her philosophy quite clearly (the numerous tirades by Rand's favoured characters ensures this), but Rand never manages to convince the reader that her philosophy is a tenable one. Rand's philosophy, from what I understand, is that big business and capitalism is good, governments and socialism are bad, everyone's simply greedy at heart, and this greed is good.
Disregarding the fact that Rand never manages to refute more than a strawman version of socialism, Rand still fails to answer some quite basic questions that would arise in the idealised situation that occurs at the end of the novel, where her philosophy triumphs. How does a society without any form of government system manage with crime or environmental problems, for example? What safeguards are put in place to protect consumers against monopolies raising the price of necessities? These are questions that naturally arise from this philosophy, and for Rand to not to answer them in twelve hundred pages is simply not good enough in this novel.
But a book review is not the place to debate Rand's philosophy; it is sufficient to say that if you do not buy into her philosophy, you really won't be enjoying this book. And I don't think too many people buy into Rand's simplistic philosophical and economic view, but I'm always open to alternative opinions.
As a general fiction novel, this book fails. Rand's characters are not characters at all, but vessels created merely to espouse her philosophical ideas for several pages (up to sixty pages for one speech, believe it or not), or to create strawmen which her favoured characters knock down with the ease of knocking down, well, er... strawmen. If the characters do not do either of these things, they advance the story forward in order to get to Rand's next speech about the virtue of capitalism or big business, or to a tragic situation which would only occur in the socialistic society Rand depicts, and would never have occured if capitalism had the reins on society. And since Rand only really has two types of characters in her novel, with only their gender and name to change between them, it's quite easy to find yourself skimming over Rand's rants.
The plot of the novel, about a woman trying to keep a railroad company afloat while the world slowly crashes, is serviceable when you don't think too hard about Rand's philosophies, and while Rand's writing style is also serviceable, is not enough to sustain the reader, either.
And twelve hundred pages was not necessary. You have been warned. 1/5.