This was a pleasure to re-read. Even in this, first of the Aubrey/Maturin novels, the characterization and dialog are fantastic.
O'Brian really nailed the exact balance of a naval adventure novel, too. The action is still there, and exciting, but the novels are always about how the people deal with it. The focus on his characters' reactions, personalities and relationships usually ends up being more tense than the threats to life and limb.