I got this movie with my BBC "Jane Austen Collection" (5 DVDs of old BBC adaptations) and didn't like it at first. It's completely different from the others and it lacks, or so I thought, one of the qualities that I enjoy in all other Austen movies: cheerful common sense. The nightmare scene in which Mrs. Richards apparently sews her fingers together was especially upsetting.
I still don't like to watch the finger-sewing scene but I do love hearing Mrs. R. saying, dreamily, while she sews, "My only acquaintance...tore my gown." This movie is now my current Austen favorite. I've watched it 7 or 8 times so far. The acting, to my mind, is incredible. The way I notice good acting is when I find myself looking up from whatever I'm doing (sewing, though not my fingers together, hopefully, or boondoggling or whatever) in order to watch the character deliver his lines. It's the turn of expression, the cast of posture, that make the words come alive -- that's what makes good acting, as far as I'm concerned.
Well, I watch almost every part of "Northanger Abbey" because almost all the actors play their roles with such charisma. Peter Firth is amazing as Mr. Tilney, the perfect blend of Bathian fop and real, masculine hero - you're not sure until the end whether he's after Catherine's money or not. I love his touch of (Welsh?) accent. Mr. and Mrs. Richards are charming: the combination of their behaviors - especially Mr. Richards' high voice, lending counterpoint to his wit and wisdom - makes them so real. General Tilney as the hard-hearted father who may possibly be a murderer is fascinating, too. And Captain Tilney, the grinning rake who is so clearly enjoying himself... and the moneygrubbing sister and brother whose names I can't currently remember - the two of them are so perfectly, at once, smart and smarmy.
The other reason I love this adaptation is that it is the most romantic of all the Jane Austen adaptations. I know this was one of Austen's weak points (well, it is as far as I am concerned): even though all her novels are love stories, it's hard to feel that her heroes and heroines are really in love at the end. And if they're aren't really in love, then what's the point? All the other adaptations I've seen (other than the early Olivier/Garson one) have pretty cold-fish kisses at the end, if they kiss at all. I don't at all like sex in movies but it really is necessary to have a heartfelt kiss in the end. And the ending kiss in Northanger is a doozy.
The over-the-top approach to costumes, music, and lighting work very well as far as I'm concerned. And the script is extremely clever - the way we are educated about Gothic romance, highlife in Bath, Cathy's normal country upbringing, etc., is very well done, as they usually are in BBC productions. Also, I like the part when the little black page does the cartwheels. And the Marchionesse, I think, was an entirely appropriate and very clever expository device.
Some people have objected that this version is the opposite of what Jane Austen intended to do in Northanger Abbey - she meant to make fun of Gothic romance, not promote it. But I don't think she meant to put "Mysteries of Udolpho," etc., down. She was just making the point that you need to distinguish between reality and fiction. And this point is made when Mr. Tilney chides Catherine in his mother's room. Besides, General Tilney was a villain, albeit a prosaic one. That point was meant to be made, surely.