When this film gets it right it really gets it right. And when it goes wrong... I'd say that a full 3/4s of the film is great. I can even isolate the bad bit. It's everything that has to do with the romance. Everything that you need to know about it is said in the first five minutes but it drags on for about 30. I'd recommend skipping that section if you can. It does nothing except explain his exile. It should have been a minor plot point quickly thrust aside. Fortunately, the period from about 0-30 and 1:00-2:19 (The End) is excellent.
There are a number of excellent performances in this film, and an equal number of terrible ones. Just like everything else in this movie the acting is either perfect or terrible. Peter Ustinov as the slimy one-eyed slave Kaptah is perfect. It is one of his best performances, up there with his role in Spartacus. Victor Mature as the ambitious Horemheb is also perfect. Again, one of his best roles. Jean Simmons is wasted as Merit, the perfect girl in love with our hero John Carradine gives a nice supporting role as a philosophical grave robber; and Michael Wilding is excellent as Akhnaton, the idealistic pharaoh who tries to bring peace and monotheism to Egypt only to see it fall apart due to his unwillingness to fight. Now for the bad. Edmund Purdom as Sinuhe is sadly miscast. This is doubly unfortunate as he is the main character. The entire film revolves around him. He actually does rather good as the disillusioned exile and the wise old man. This is because of his sorely limited range. He doesn't seem able to put any passion into his words. This is especially apparent during the love scenes which are beyond awkward. He spends the last half of the film as an old man, a performance at which he is decent enough at. He does have the perfect voice for the character. The less said about Bella Darvi as Nefer, the treacherous Babylonian woman, the better.
The costuming and sets are magnificent. This is the only film that I know of that attempts to depict life in Egypt that isn't overshadowed by Jews or Romans. The film takes place in the 14th Century B.C. which is before even Exodus. The only monotheists are the pharaoh Akhenaten and his followers. There is the same strong element of religious zeal that can be found in most epics, but it is done differently and it only shows up at the very end. An interesting note: by having Akhenaten followed by Horemheb as pharaoh, the film completely skips over the most famous pharaoh of all: Tutankhamen. Seems kind of a strange thing to do when using that name could increase awareness of the film.
Be warned: this is a 1950s epic film. If you don't like that type of thing then don't expect this one to be different. It is different, but it is still an epic. I appreciate this film, and I appreciate what it did and what it tried to do. This is a film that should be better remembered than it is.