In the siren episode, Joyce tries to imitate a piece of music, starting with the warmup, which pre-figures themes to come:
BRONZE BY GOLD HEARD THE HOOFIRONS, STEELYRINING IMPERthnthn thnthnthn.
Chips, picking chips off rocky thumbnail, chips. Horrid! And gold flushed more.
A husky fifenote blew.
Blew. Blue bloom is on the
Gold pinnacled hair.
A jumping rose on satiny breasts of satin, rose of Castille.
Trilling, trilling: I dolores.
For me, this is just obscure for the sake of obscurity. Unlike the other obscurities in the novel, I think that this is one that gives no enjoyment if you're not already in on the joke. By contrast, the changing literary styles in, say, the "Golden Oxen" episode are fun to read even if you don't get the pregnancy symbolism. Since starting to write this entry, I've begun the "Cyclops" episode, and the same thing is true -- the mix of literary styles is very funny, even if you don't understand quite why they're there.
By contrast, the "Wandering Rocks" episode seems like an exercise in lucidity. I understand that that's one of the traps Joyce has laid -- the chapter is not quite as straightforward as it seems, with its tricks like referring to the wrong Bloom -- but it's still a section that's very rewarding even on the most surface reading. Joyce's portrait of Father Conmee is satirical and affectionate at once; he manages to throw a lot of pathos into the short bit with Stephen's family; and so on. I can imagine excerpting just this chapter to hand to someone as an independent short story, called "An Hour in the Life of Dublin" or something.
As I mentioned above, I've just started on the "Cyclops", one of my other favorites, and a huge contrast to the clarity of "Wandering Rocks."