A couple things: First off, everyone's heard of Ulysses, and everyone has their own notions of what they expect from a book, what they expect from Ulysses in particular, and how they feel about experimental literature in general (though by today's standards Ulysses appears vastly less experimental than, say, Finnegan's Wake). So basically, if you don't think you'll like Ulysses, you probably won't. And no, it's not a casual read. If you're willing to do some homework, though, which in my case included some Homer, Shakespeare, Freud, and Irish history (though I could go on), it just might be worth your time (lots of time) to slog through all 900+ pages of the thing. But that's just my two cents.
The real reason I'm writing this review is to steer people away from the 'reader's edition' of Ulysses--that's the reason for the two stars. This is not the novel as Joyce intended--it is an adaptation by Danis Rose, and reflects what he (Rose) thought was 'accurate.' Though the changes he makes are minor--and, in all fairness, may correct oversights made by Joyce--I am offended by the idea that an editor has the ability to take an important and influential work and make changes as he sees fit. The fact that this edition was ever put to print debases the role of the artist (any artist), and reflects the increasing trend toward commercialization and dumbing-down of art in favor of turning a profit.
So--is Ulysses the greatest artistic achievement in any medium, ever? I don't know, and whether I think so is irrelevant anyway. But if you want to find out for yourself, please, PLEASE, at least read Joyce's words, not Rose's.