For starters, the Socs and the greasers have vast differences in physical appearance. While the Socs, who come from money, are well groomed and neat in appearance, the greasers, who hail from the proverbial wrong side of the tracks, “rarely [bother] to get a haircut.”
The other obvious difference is socioeconomic status. The Socs come from wealthy families, while the greasers do not. This difference can be plainly seen in the cars driven by members of the respective groups. Thanks to their money and privilege, the Socs are far more highly regarded than the greasers, who have been branded as “trouble.”
Ponyboy describes the greasers as being wilder than the Socs. This is far from saying that the Socs are law-abiding young citizens, but they are not as wild as the greasers, who “steal things” and “have a gang fight once in a while.”
In terms of similarities, both the Socs and the greasers are going through the same phase of life: they are growing up in a world in which they are expected to conform to a particular image. Both groups grapple with self-identity issues, with the Socs not living up to what is expected of them and the greasers, with their dysfunctional families, often feeling abandoned.
Members of both the Socs and greasers love a fight. Both groups experience the angst and emotions which are synonymous with the teenage years. Also, Socs and greasers both resent the stereotypes to which they are expected to conform.