Exposition is rarely as fun as it is in Martin Scorsese films. He can make time fly while having the film being 70% exposition but it never feels like I'm being told too much. The part where Sam and Nicky explain how the casino works is so great, it is loaded full with exposition but it serves a purpose.
Sharon Stone's and Joe Pesci's characters are annoying at certain points in the film but I think that makes the movie even better.