I took a seminar on it college and have loved it ever since.
Mrs Jerry and I even got married on Bloomsday : June 16th
There are some sections that REALLY bog down, I will admit, but Molly Bloom's solliloquy at the end makes it worth slogging through.
Did I mention I was book nerd which also helps??
ETA : FWIW I though Gravity's Rainbow was a much more difficult read
Ulysses is one of those books that I would really like to devlop the stamina to get through. I've gotten maybe a hundred or so pages into it before I just run out of steam.
In any case, my list of multi-read books are
Illuminatus! Trilogy by Wislon and Shea - at least four times, although I may have lost a read or two in there
Phantoms of the Mind by Ramachandran - three times
Several Discworld books I've read four times or more, I think I've read all of them at least once - which is a feat in itself
The Incarnations of Immortality series
Amber series
Time Enough for Love, Stranger in a Strange Land, Moon is a Harsh Mistress and Cat who walks through walls all at least three times
Cat's Cradle, Slaughterhouse 5 - Twice for Cat's and I've lost count for Slaughterhouse
HP Lovecraft - I'd say that I've read them all, but everytime I think that, I find a new collection that has one that I've not read yet. My favorite, and most read, is Statement of Randolph Carter with Mountains of Madness coming in a close second. A friend just lent me a Clark Ashton Smith collection, I'm sure I'll end up re-re-re-reading at least parts of it.
Cryptnomicon - Twice (personally, I think that reading that twice is worth at least three reads of some lesser books, just for a volume discount)
H2G2 - the first five of the trilogy I've read many, many times and I've just started Eon Colfler's book.