Other people have responded in other ways, so I won't respond regarding her philosophy. I'll respond in a purer way that nobody else has: she writes bad prose. Her sentences are ugly, overlong, and lack concise flow. So by the definition of literature as the beauties of language, her work is imperfect and, in the case of
Atlas Shrugged, actively
bad.
I daresay I've read Atlas Shrugged more times than you have. Furthermore, though I could be wrong, I would argue that I've memorized more of the central concepts and analyzed them more thoroughly than you have. Judging from how you've written on this thread, you're still operating from a very shallow interpretation of her works, which is antithetical to her own ideas.
The central flaw of Atlas Shrugged is that it denies external possibility. Given her own hypothetical world, it follows impressive logic. However, it ignores the fact that people are not so easily judged. A former girlfriend of mine was an Objectivist and simultaneously an irrationalist. She believed in man as an end unto himself, but also that everything was subjective, there was no absolute truth - and she was a believing Christian on the side. The problem with Ayn Rand's writing is that the two are not necessarily incompatible. You can believe in what she writes and still think that things are subjective, and that truth is difficult to find, and while she would argue that that is a corruption of her ideas, and it is, Atlas Shrugged does not define itself well enough.
Part of the problem is the nature of language, which is subjective. If I tell you that I'm nice, it could mean that I am "kind" or that I am "accurate". If I call my friend a "motherfucker" it means something different to him than it does to Oedipus. Similar, "objectivity" does not have an objective interpretation. Neither does "selfishness". People will never agree over these definitions. Objectivists don't agree over them in their entirety. By that nature, yes, everything is subjective.
But that's beside the point. To give a quick summary of other flaws, I'd say that her writing is preachy, her characters are one-sided, there's no observation of physical stimuli (which is to say, the nature of bad things happening to good people on grounds other than human interference, which leads to questions of philosophy that she neatly ignores), and her book is about three hundred pages too long, drags in the opening, in the latter half of the second part, and John Galt's speech is wholly unnecessary as part of the work. Feel free to respond.