I thought it was great until Part III, Chapter 7, when she spent the entire chapter rehashing concepts that she had beaten to death already, without advancing the plot at all. I read it all the way through the first time, but skimmed Galt's soapbox speech the second time around.
Still, I think it is all around a great piece of literature, and everyone should read it. Unless of course, they don't also read Marx, Orwell, Locke, Le Guin, and the works of other literary thinkers. If you aren't going to get a well-rounded view of things, might as well not read at all.
For those of you who have read the book, head on over to
this thread to offer your opinions on Galt's Gulch.