<p>The most important thing to know about the “defining characteristics” of these universities, and of the dozen or so peer universities, is that (a) generally, they are large, extremely complex institutions that cannot even remotely be characterized accurately in a slogan or two, and (b) their overwhelming similarities completely swamp their relatively small differences. People overvalue the differences, especially when they are choosing between two colleges, but the kinds of differences the OP talks about in the first post are the equivalent of comparing equivalent cars from Lexus, Audi, BMW, and Mercedes.</p>
<p>Also, very, very few people get to choose among these colleges. Most people are thrilled if they are offered admission to any one of them.</p>
<p>There are three differences that DO matter, and that extend to peer colleges as well:</p>
<ol>
<li><p>Liberal arts-only vs. specialized schools. Penn and Cornell offer a whole spectrum of specialized schools, Columbia has a separate engineering school, and the rest offer only a core liberal arts education (albeit with an engineering option everywhere). If you are interested in the liberal arts curriculum, it doesn’t matter much which college you choose, but if you are interested in nursing, or business training, you can’t get that everywhere.</p></li>
<li><p>Size matters (somewhat). Bigger communities mean more opportunities, more diversity, more stimulation, but at a loss of intimacy and focus on undergraduates. Each of the colleges strikes its own balance.</p></li>
<li><p>Location, location, location. The effect of the college’s surroundings can be fairly important on what it’s like to be a student there. Columbia is a very different place than Dartmouth, and it’s not really because it has a core curriculum. For starters, there’s an awful lot more to do off campus at Columbia (and that can be good or bad, depending). Plus, wealth means a heck of a lot more in Manhattan than it does in Hanover.</p></li>
</ol>
<p>What’s really not very different is the kinds of students they have. Not everyone applies to all these colleges, but the same set of people tends to apply to various of them. And the colleges often deliberately admit against the college’s “type,” in order to get a less monolithic student body. So Yale may be somewhat artier than Dartmouth, but Dartmouth takes care to admit many, many arty kids, and Dartmouth is full of arts opportunities. You could switch the student bodies of these colleges in the middle of the night, and not more than maybe 10% of each would be significantly more or less happy at the new college.</p>