Culturally, Brandeis is actually quite a diverse place. There are many different ethnic groups besides Jews, and the student groups representing them are extremely active in promoting their cultures and providing entertainment as well as good food. Culture clubs represent just about every possible ethnic group and have quite large followings. It would be very hard for students to feel culturally out of place.
Religiously, Brandeis is far more homogeneous. While the Brandeis Humanists have a sizable following and the Christian groups also exist, Judaism is no doubt the strongest religion on campus, even if it's believers are only a plurality. The number of kippahs and Stars of David can attest to this fact. However, this does not mean that there isn't absolute freedom of religion here as well. Judaism is strong here, but Gentiles aren't bothered by it at all.
Geographically, the majority of students at Brandeis come from the Northeast. Residents of New England, New York, and New Jersey form the majority of people here. Even so, there are many Californians and other Westerners, as well as people from the Southeast. The international presence here is also noticeable, with rather large groups of students coming from France, China, Turkey, Israel, and many other countries around the world. Regardless, students from various places mix very well.
Financially, Brandeis has also a diverse mix. While I have friends who already own really nice cars and have no problem paying for school and other expenses, there are just as many who must pay their own way and have little extra spending money. Most students here come from middle class backgrounds, and must pay at least part of their tuition and spending.
Politically, Brandeis is quite leftist. The few Republicans here and there tend to have their ideas shunned and ignored by the liberal majority. While radical hippies are also rare, the mainstream opinion makes groups like the Democrats and Democracy For America very strong. Activist groups are always enthusiastic, as almost all students have some sort of political opinions. One will never find the political environment at Brandeis to be lacking.