I polished off the Fountainhead in about a few days in high school, and that's when I found out that Atlas Shrugged was the more relevant Title. I thoroughly enjoyed the Fountainhead and many of the points it made (both in Architecture and as a philosophy of life in general), so I picked up Atlas Shrugged and read that in a week or two.
The question "Who is John Galt?" has forever been branded on my mind (and has become sort of an inside joke with anyone who has atleast read the first paragraph of the book). I found the story to be very interesting, although I had a bit of a beef with Ayn Rand's patronistic belief that a very romantic style of writing (read: dense and at times slow) is the only type of lucid writing that will survive in literature. She obviously has never heard of Hemingway or, on the flipside, Joyce or Faulkner. I also had a bit of a beef with the fact taht almost every signficant female character in her works has a rape complex. It gets tiring about the umpteenth time a female character is subjected to "domination in his wild hands."
As a didactic work (which Ayn Rand intended all her works), Atlas Shrugged fails miserably. Fountainhead, while it did tend to hit you with a bat at times with its philosophy, still put a lot of emphasis on the plot and flow of characters. I sympathize with Roark's cause, while at the same time I don't have too much sympathy for Keating. Meanwhile, with Atlas Shrugged, she does nothing to make her arguments completely sound and lucid. I mean, her attacks on postmodern philosophy are semantic at best (paraphrased quote: "Can you question the existence of a bullet as it imbeds itself into your body?"), her praise of "enlightened selfishness" is more the naive impractical philosphy that it is, as oppossed to the simple, more existentialist message in Fountainhead. She kills off people whose only crime was caring about social welfare, putting them into the same category as people who are dangerously unskilled for their jobs (and are there because of some welfare program) and end up wiping out groups of innocents. Furthermore, the 50-some odd page monologue at the very end had a notable lack of tact. Oh yeah, it was really boring, too. If you couldn't figure out the message after 900 pages, a 50 page monologue doesn't help you out that much.
So, in conclusion of my ranting, Rand is ultimately someone who tried to develop a philosophy, which ultimately seems more like an extension of existentialism, but really failed in putting forth a cohesive reason for its existence.
EDIT: I voted for the choice along the lines of objectivism is a compelling philosophy I can appreciate, but it's ultimately unworkable. After reading the Fountainhead, I enjoyed a brief stint as an objectivist (but then against, this was also the time in my life I experimented as being a solipsist, so that's not saying much), but now I hold myself as an existentialist/relativist. I find it patronizing that one woman dictates what is the "right" way to live (aka "enlightened selfishness") and the "wrong" way to live (anything having to do with selflessness). Ironic (maybe hypocritical?) that I favor smart growth controls? :-D Oh yeah, her metaphysics and epistemology suck, too. (Sorry, objectivists for my bluntness.)