Hilarious... best movie either Ackroyd or Murphy have done.10/10
I skimmed over the comments to this movie and was heartened to see that so many people love it like I do. It just doesn't seem to be considered by the mainstream to be in the same league as, say, "Beverly Hills Cop" or "Coming to America" when talking about Eddie Murphy's movies, but the fact is that this is hands down his funniest part ever. And Dan Ackroyd is equally hilarious as the (at first) repulsively elitist Louis Winthorpe III. Add the stellar supporting cast, particularly Don Ameche and Ralph Bellamy as the Dukes, Paul Gleason as the slimy Clarence Beeks, Jamie Lee Curtis as Ophelia, your standard hooker with a heart of gold (rarely done as well as here), and Denholm Elliott as Coleman the butler, and you hit a rich vein of comedy gold.
The plot is a classic farce situation. The Duke brothers, who clearly feel they are above everybody else, make a bet, for one dollar, over whether anybody regardless of breeding can, in the right environment, become an upper-crust gentleman. So as an experiment to see which one is right, they work circumstances so that the rich Louis Winthorpe III is turned into a miserly bum, while they have Billy Ray Valentine (Murphy) take his place. He takes over Louis's job, his house, and his standing in the community. Realistic? Well, no, not really, but this is a farce, so it doesn't really have to be. It is, however, hilarious, which is exactly what a farce should be.
If there's a running theme in this movie, it is duplicity and mistaken identity. People are constantly being mistaken for something they are not, or forced into a situation where they become something they are not. We see this happen not only with the two main characters in the basic plot, but also with Billy Ray pretending to be a Vietnam veteran, then a karate master; Louis, who despite all appearances as a wimp, claims to have stood up to Billy Ray during their earliest encounter in the movie, when he actually hands Billy Ray his suitcase, setting him up for an arrest, when he was not actually trying to steal anything; Ophelia, who for a price pretends to know Louis outside the police station, further besmirching his name; all three plus Coleman, who each dresses up as a different hilarious ethnic character to trick Clarence Beeks; and Beeks, who in a subsequent scene is mistaken for an actual gorilla because he's wearing a costume (Al Franken and Tom Davis as the baggage handlers, marveling over how human the "gorilla" appears, are priceless).
Eventually, Billy Ray finds out what is going on, and gets together with Louis to turn the tables on the Dukes. Ophelia (who has fallen for Louis) and Coleman (who feels guilty and used over his part in the whole ruse) help them out. Do they get their revenge? Watch the movie and find out. It will be well worth your while. This is easily the funniest movie either Ackroyd or Murphy have ever done (its only real competition in this regard is "The Blues Brothers") and to think this was originally meant as a vehicle for Gene Wilder and Richard Pryor is odd, because it's hard to imagine either of them in the parts done so well by Dan Ackroyd and Eddie Murphy. John Landis keeps the pace going at a nice fast speed, and being a native Philadelphian, the locales and opening montage (including a scene of the Rocky statue) are a kick. But of course you'll love this movie even if you're not from Philly.