I loved Atlas Shrugged (though it did take me a while to complete the speech), and coincidentally, I'm working on Dune right now, but I'm honestly struggling, and I haven't even reached page 100 yet.
It's just a little slow for me. Though having seen the movie and the miniseries, and knowing a fair bit of the Dune lore may be taking some of the "discovery" out of it.
Except for the speech, I didn't think Atlas Shrugged was slow at all, just LONG