What are the main theological differences between Reformed Baptists and other Baptists?

I have recently met people who are Reformed Baptist. However, I'm having a hard time understanding what their major beliefs are, especially in comparison to other Baptists. The Wikipedia article gives a good overview of the history of the group, but doesn't summarize the major theological beliefs. Do they still hold to the defining Baptist tenet that only adult baptism is valid? Are there other major differences between them?