I picked this nautical adventure up after seeing the movie, which I thought was quite entertaining (and had Excellent sea battle scenes). It's the first of a very long series of similar adventures by the author. After reading it, I could see how the series could stretch on - it doesn't really have a tightly crafted plot, but is more of a realistic account of events at sea: "this happened, and then this happened and then we met this ship, and then this battle happened, and then we went somewhere else, and then..." etc.
O'Brian definitely did his research - the life at sea seems believably detailed, and he says that all the battles he describes, etc, are based on actual incidents of the time period.
However, to me, the style of the novel was a bit lacking in, well, romance and adventure. And emotional interaction. Things will happen, but you don't really see them happening, or ever find out about how the people involved felt about it. Some of the incidents are quite, umm, salty. (Including whoring, venereal disease and even bestiality (death penalty for that one!)) But it all happens off-screen as it were, and the reader feels very removed from it.
Perhaps this is why (to be stereotypical) these books have traditionally been more popular with male readers? I don't know.
Glad I read this, but I don't feel the need to seek out the rest of the series.