LACs pack substantially above their weight despite being a destination for under 2% of college-matriculates.
Of the top 50 schools enrolling the students with the highest SAT/ACT scores, 18 are SLACs:
http://www.businessinsider.com/the-610-smartest-colleges-in-america-2015-9
The top 50 feeder schools for a selection of elite medical, law, and business schools has 22 SLACs:
https://hubpages.com/education/Wall-Street-Journal-College-Rankings-The-Full-List-and-Rating-Criteria
Among the top 25 schools leading to the highest production of PhDs, 15 are SLACs:
https://www.swarthmore.edu/institutional-research/doctorates-awarded
According to the component ranking Forbes uses for its combined university/LAC ranking, several LACs rank in the top 50 for production of "American Leaders" (scientists, CEOs, politicians, etc.), including Swarthmore and Amherst in the top 10. Several LACs also rank in the top 50 for alumni receiving competitive undergraduate fellowships, including Pomona and Williams in the top 10:
https://web.archive.org/web/20150131081828/http://centerforcollegeaffordability.org:80/uploads/component-rankings-2014-v2.pdf
LAC students (classified as "Baccalaureate Colleges: Arts & Sciences Focus") are substantially more likely to do research with faculty, internship/field experience, study abroad, and a culminating senior excercise than students at any other classification of colleges, including R1- highest research activity:
http://nsse.indiana.edu/2017_institutional_report/pdf/HIPTables/HIP.pdf
Some LACs have among the highest graduation rates and most generous financial aid policies of any college or university in the country:
https://www.kiplinger.com/tool/college/T014-S001-kiplinger-s-best-values-in-private-colleges/index.php?table=all
Retention rates at the top LACs are consistently above 90%, consistently above the national average of 66%:
https://www.usnews.com/best-colleges/rankings/national-liberal-arts-colleges/freshmen-least-most-likely-return
One consistent pattern I've seen, based on the Niche survey, is that the satisfaction with teaching is incredibly high. Compare the responses for "What Students Say about Professors" with:
Bowdoin-
https://www.niche.com/colleges/bowdoin-college/academics/
Middlebury-
https://www.niche.com/colleges/middlebury-college/academics/
Colby-
https://www.niche.com/colleges/colby-college/academics/
Yale-
https://www.niche.com/colleges/yale-university/academics/
Boston U-
https://www.niche.com/colleges/boston-university/academics/
UVA-
https://www.niche.com/colleges/university-of-virginia/academics/
The question about "Students say professors care about their students' success." is especially relevant. At LACs, the undergraduates are the professors' first, second, and third commitment. They are invested in their personal development outside of the classroom. Even at "large" classes (which will almost never be over 50), a professor will personally monitor and get to know every student. All labs and instruction is from experienced professionals, not TAs. These professors depend on the undergraduates for research (since there are no graduate students), making research incredibly easy to obtain. At the most elite end of LACs, the professors have overwhelmingly gotten their PhDs or terminal degree from the most prestigious universities in the country, so the level of expectation is high:
http://catalog.swarthmore.edu/content.php?catoid=7&navoid=175
By no means are these experiences unique to the LACs. Some universities, like Dartmouth and William and Mary, as well as restricted honor's colleges at state schools (where courses are capped and set only for the honors students), all are similar. But it defines them to an extent it doesn't at the traditional university.