It's a very good collection. They're pretty unusual as most short stories go, with the emphasis on character, thoughts and the presentation of the moment, rather than plot. They also add up to an vivid depiction of Dublin at the dawn of the 20th century. Joyce said he wrote Dubliners with a style of "scrupulous meanness", and although on the surface it seems like the easiest of his books to read, it's very subtle in its effects.
Highlights for me are "Ivy Day in the Committee Room", which explains a lot of the Irish politics that form the backdrop to Joyce's other novels, particularly the importance of Parnell. "Counterparts" is a disturbing little tale of a physically imposing man who puts up with abuse from his short and shrill boss all day at work, then gets drunk, goes home, and beats his children. Nasty, but extremely well told. The best stories in the book, for me, are the first and last "The Sisters" and "The Dead". I can't really comment on them, or I might flood the page with reams of adoring prose, except to say that they could almost have their titles reversed due to the content of the stories - anyone else think so?
Having said all that, though, Dubliners is somewhat in the shadow of Joyce's three great masterpieces: A Portrait, Ulysses and Finnegans Wake. I spend so much time on them that I don't look into Dubliners as often as I should - thanks for the reminder!