Since others have written some very well written reviews of "Southern Comfort" I don't want to repeat what they say however a few points require clarification.
First, what this film is about. It is not, in my opinion, merely about the traditional urban/rural divide. That divide exists in the film as it does in real life. But that is not the point of the film. Nor is it an anti-white or anti-Southern screed. Although it takes place in the South it could take place just about anywhere when one realizes what the film is really about. Also both the "survivors" and the "villains" in the film are white Southerners. The "survivors" being two Louisiana National Guardsman - Spencer (Kieth Carradine) and Hardin (Powers Boothe). The "villains" being Cajun fisherman/hunters out in the swamps of Louisiana.
No, what "Southern Comfort" is really about is what happens when arrogant fools invade another people's land and start indulging in violent and hostile acts, including destroying the livelihood of the native people (e.g. cutting their fishing nets and stealing their boats), shooting at, seizing, and taking prisoner innocent locals, blowing up their homes, abusing and torturing them (sounds all to familiar), and then wondering why they are hated so much and why the native people attack them. The message is really that simple.
It was captured in a short dialogue after the "survivors" are shown to be the last two left among the guardsmen. When they are confronted by a shotgun toting one armed Cajun (who was previously their prisoner) brilliantly played by the late Brion James, Hardin asks the Cajun, "Do you mind telling us what this [the war with the guardsmen] is all about?" The Cajun responds, "It's real simple. This is our home and and nobody f***s with us here." For that reason the advertising slogan for the film - "The Land of Hospitality...unless you don't belong" - is wrong. It should have read "The Land of Hospitality...unless you misbehave and start mistreating and abusing the locals!"
If the guardsman hadn't behaved badly then they would not have had much trouble with the locals in the first place. Also, the Cajuns in the small town at the end of the film came across as quite normal and hospitable to me. Only the "swamp rat" Cajuns come across as threatening and THEY were only fighting back against violent intruders. So I have to disagree with the assessment by some that the film is anti-Cajun, anti-white, or anti-Southern. On the contrary, one of the "heroes" (i.e., survivors) is a white Southerner from Baton Rouge (Spencer played by Keith Carradine). As for the Cajuns shown in the small town, they were not actors. They were real people that were shown honestly and fairly - enjoying good food, good company, good music, and dancing.
To sum up, "Southern Comfort" is an outstanding and extraordinary film in its own right. The acting is persuasive and very convincing, especially from Fred Ward who plays a very menacing type and, of course, the much underrated and underappreciated Powers Boothe who plays the "outsider" from El Paso, Texas. The direction by Walter Hill is superb. The cinematography from the first frame to the last by Andrew Laszlo is lush, rich, and luxuriant. (It makes me want to visit the Louisiana bayou to see it for myself.) And last, but not least, the music composed and arranged (and played) by Ry Cooder is both mysterious and seductive. Few films have ever enjoyed such a perfect marriage between image and music as "Southern Comfort." The only other film that has this quality that immediately comes to mind is Carol Reed's "The Third Man" which featured the hypnotically beautiful zither music by Anton Karas. Karas and Cooder both share an indescribable special quality that is evident in both films.
Halliwell's Film Guide gives "Southern Comfort" its top rating - four stars - and if you know anything about Halliwell's you know how difficult it is for any film to get four stars. I think it justly deserves that rating which is why I don't hesitate to recommend it to everyone without any reservations.