I was sure I was going to prefer the Vivien Leigh version, but in the end, the Greta Garbo movie wins hands down. Greta Garbo showed far more range as an actress, especially as happy and in love with Fredric March/Count Vronsky. Her broad smile lit up the screen, while Vivien Leigh comes across as posturing and making faces of perhaps hoping for love but she is not capable of looking absolutely happy. Leigh is known to have had some deep mental troubles offscreen, and after watching a couple of her movies (Gone With The Wind of course, Hamilton Woman, Waterloo Bridge and this one) I have to say she comes across as a bit limited in the range of her acting. Garbo was a superstar for a reason. Given her reputation as a recluse after she retired early from the movies, I didn't expect her to convey so much emotion on screen, but what a magnificent job she did.
The Garbo movie is also better for matters unrelated to Garbo: the scenes are better cut, better filmed, changes in minor plot points are better chosen. Let's commend the now quite forgotten Clarence Brown for his incredible work as a director. (Brown's films have received 38 Academy Award nominations and directed Joan Crawford 6 times and Greta Garbo 7.) First off, the Leigh movie begins with the same scene as in the novel, Anna Karenina's brother sleeping on the couch because his wife decided she would no longer put up with his infidelities. But the Garbo movie starts with the scene where a regiment of Russian officers including Vronsky play a party game where they have to down three shots of vodka and crawl under a long table and repeat until they pass out drunk, and Vronsky wins. A 1935 movie that starts with a scene like that has spunk. The use of lighting and framing is far superior in the Garbo movie, and (spoiler alert) at the end Vronsky enlists in a regiment going to fight the Turk-Serbian war, he argues with Anna when she finds out, she goes to the train station to say proper goodbye to him and she finds him chatting with a young lady his mother brought, whom Anna had also noticed when she went to the opera with Vronsky. So she never says good bye to him and then throws herself under a train. The expression on Garbo's face when she looks at the train passing by before she jumps is breathtaking. The last scene shows Vronsky talking about his guilt at the way he handled their last conversation (he never finds out she went to the train station). In the Leigh movie, Vronsky goes to see his mother in Moscow, Anna takes the train after him, and then at a stop she stands in front of the train so she gets run over when the train leaves the station. The last scene is her lying dead on the tracks, looking as beautiful as ever, after the train has run her over.
My only reservation about the Garbo movie is that the Karenin character is so caricatural one has to wonder why she ever accepted to marry him, while in the Leigh movie there is some level of affection between Karenin and Karenina and one can imagine that Anna Karenina was once like Kitty, marrying someone although she wasn't in love with him because she thought he could offer other things such as stability, having a child, and then becoming dreadfully bored and dissatisfied with her life. As Vronsky, Fredric March demonstrates why he was one of the leading men of his generation, but Kieron Moore in the Leigh movie also excels as a younger Vronsky besotted with Anna.
Both movies are very good, but Garbo's is one notch above Leigh's.