Google tells me that, statistically, Amherst, Vassar, Grinnell, Smith and Pomona are the most economically diverse of the top LACs. Kenyon, Colgate, Colby, Claremont McKenna and Bates are among the least economically diverse.
In racial diversity, the most diverse of top LACs are Wellesley, Amherst and Swarthmore. The least racially diverse are Washington and Lee, Sewanee, Kenyon, Colgate, Hamilton, Colby and and Bates.
Not sure what either of those things means to you, if anything. It’s perfectly ok if they are not significant in your decisionmaking.
My D visited Williams, Amherst, Swarthmore, Middlebury, Tufts, Wesleyan, Haverford, Pomona and Claremont McKenna last year in her search. All of them had their charms, and not one of the felt as preppy as, say, Dartmouth.
Swarthmore was not at all run down (seriously, who said that, that campus is beautiful). It felt very intense. Not sure that all the students were enjoying their time there. She thought she might like it, but was wary of the potential “wallowing in misery” vibe.
Williams was very sporty (in a good way), but felt very, very isolated. She couldn’t see herself there for 4 years.
Middlebury was also isolated, but not as much as Williams (but even colder). The campus is beautiful but strangely stark and grey. The vibe was an odd combination of international and preppy. The town was a little bit bigger than Williams. She liked it.
Pomona was the essence of successful California, which is good and not so good at times (we are Californians). It felt like people constantly felt the need to downplay how hard they worked, even though they worked very hard. That really is a California thing. She liked it.
Claremont McKenna was very pre-business-school and “leadership” oriented, as opposed to intellectual. It didn’t have frats but it felt kind of like a big frat (if that makes sense). She didn’t like it.
Tufts feels more urban and more compact than any of the others and is a bit larger. She liked it.
Wesleyan was hard to read. It was freakishly cold that day, it was out of session, and we didn’t get much of a feel for it, good or bad.
Her favorite was Amherst, and that is where she is going next year. It wasn’t perfect, no place is, but it felt very friendly, and the students seemed high-achieving without being miserable about it (like Swarthmore) or having to put on a 24/7 show pretending that they weren’t working at all (like Pomona). The surrounding towns are very appealing with the other 4 colleges there.
You need to visit as many of them as possible and read other sources to get your own feelings about these places. Every single one of the posters on this site is biased (including me). We have our favorites (usually where we or our kids go) and we have ones that we irrationally dislike, and our information simply isn’t very reliable or complete.