Current 1L weighing in on the atmosphere discussion. I was sort of worried about competitiveness/coldness at law school, generally, and was very pleasantly surprised about how friendly people tend to be at CLS. From talking with friends at other law schools, I have gotten the sense that CLS is actually less competitive than the typical t15 school. For example, I had a stomach bug last week and missed a day. At least one person in every single one of my classes offered to let me copy their notes. I had only spoken to all but one of the people who offered once or twice before, if that. So, while they're are, of course, some people that are cold and competitive, I'd say that all in all CLS students are more supportive and friendly than they are competitive and cold.
Also, I think it helps that 1Ls take legal methods, which is pass/fail, before regular classes start. It provides an opportunity for students to get comfortable with classes, reading, each other, etc.