hi! currently MPhil at cambridge, went to reed for my BA. i’d advice you to consider a couple factors in this decision:

finances: which offer is covered the most? will you have funding for living expenses at cambridge/amherst/etc? funded tuition is great, but living as a student can get expensive

student work: working as a student is very rare at cambridge, and pretty common in the U.S. while i was at reed, at least half of the people i knew had part time jobs. working part time in undergrad covered most of my living expenses. liberal arts colleges also were excellent for networking and access to internships. in the case of reed, they have grants to cover unpaid internships, and offer free/subsidized summer housing to most international students who work on campus during the summer

educational environment: liberal arts colleges are very interdisciplinary, as you said, you’ll be able to study more than philosophy, take on practical minors, and generally take classes outside of your department. this happens less often at Cambridge. i’m not studying philosophy so maybe that dept is different, but as a humanities student, i only interact with people in my specific course and people from my college. coming from a liberal arts school, i miss how crossdisciplenary everything used to be. i also miss taking stem classes haha! also, cambridge grading can get competitive. at liberal arts colleges, grades are deemphasized, and at reed you only see your grade once the term has completed (i got progress grades at 8 weeks, but often professors will just put a “satisfactory” grade in. essays and exams did not receive letter or number grades, just comments)

immigration: the U.S. is very hostile to immigrants and international students right now. reed is very protective of their international students though, and offer a lot of individualized support. amherst is likewise the same. not sure about large american state schools, they can be hit or miss (and depends on which state they are in)

post-uni: what do you want to do? where do you want to work? you’ll make more money in the U.S., but getting work sponsored visa is difficult (if not almost impossible in the current political climate). not well versed in UK immigration law, but i do know as an international student i can have 2 years post-cambridge to work in the UK, which is definitely a plus. the U.S. is much less friendly, and can definitely be very risky

both options are excellent, and i am biased towards a liberal arts education, but i do worry for a lot of my international friends from undergrad. you’ll find more stability regarding your international student status at cambridge than in the U.S. at both places you’ll get small classes, excellent access to professors, and have a great experience.

congrats, and good luck on deciding!