Exactly as robotw said. I have the whole set, and have read them all, now on my third read-through. The writing is really excellent, the atmosphere and background are so deep and well-researched, and the characters (especially the male characters, O'Brian's one weakness being the limited exploration he gives to female characters) are very richly portrayed, you will enjoy reading and re-reading if you catch the bug.
Compared to the film (which is excellent, but a compound of lots of the book stories) the books are much more richly descriptive, in some cases based more on land than at sea, and show a much wider range of the nature of the characters, especially Maturin (who pretty clearly has a strong whiff of O'Brian self-portrait about him). And, crucially, the humour comes out more strongly in the books - tinder-dry, understated 19th century humour, but funny for all that.
If you find the Austen-esque langage and dialogue a bit hard going a first, it's worth persevering - it might take a chapter or three to 'get your eye in'. And the O'Brian fanbase (especially in the US, bizarrely) is so well established that there are companion books and websites to help you out if the jargon defeats you at first.
Enjoy!!
