<p>I think math and physics majors at Princeton get the A.B. Personally, I wouldn't worry about that. Check out this site:
<a href="http://www.princeton.edu/main/academics/departments/%5B/url%5D">http://www.princeton.edu/main/academics/departments/</a></p>
<p>Otherwise, I'll comment on Caltech, because I don't know about the other places. The size of Caltech is an advantage from an academic perspective, because it has similar resources when compared to the other universities. Since there are so few people, there are lots of opportunities to work with faculty. From a social perspective, having a small number of people means that at some point you will know most of the undergrads, so when you go to parties e.t.c. you will always see the same people. Also, parties at Caltech are not going to be as large as parties at Big Ten schools that have thousands of people. </p>
<p>Similarly, the ratio affects social interactions in negative ways. Its not quite as bad as it seems numerically because the guys tend to be more socially inept than the girls on average. I would say this is the greatest disadvantage about Caltech (combined with the small size of Caltech, it is a little worse). There are, however, other colleges in the LA area,
and those colleges have lots of girls. If you are interested in Caltech, you should learn about the undergraduate housing system, since it is important to student life (it is like a fraternity system, but not identical to one).</p>