Grinnell and Oberlin are such excellent opportunities. If I had a kid considering these social science/humanities options, I’d lean strongly in this direction, actually.
I think sometimes it’s easy to read too much about college culture into acceptance rates (e.g. RPI has a higher acceptance rate than a lot of schools but the students there have academic profiles comparable to those at some of the more rejective state universities and liberal arts colleges.) For what it’s worth, Oberlin and Grinnell accepted students have very similar standardized test scores (with roughly half the students at each school submitting tests for consideration).
Oberlin impressed us when we visited last year, and I was not expecting to be impressed. I think I had a sort of caricatured idea of it in mind due to it being a sort of avatar of liberal excess in the minds of (I guess the media?) It felt like a life-of-the-mind sort of school to us. The students we met seemed purposeful, independent, mutually supportive, intellectual. The town is surprisingly hip (has a terrific bakery, great Thai food, amazing pizza, farm-to-table stuff, a huge bookstore, etc.) and is basically contiguous to the campus. The conservatory (to me) is a feature, not a bug – you have world-class musicians teaching and performing all the time. The campus architecture is diverse and interesting and campus is spread out over a spacious 440 acres. I appreciated how many students were pursuing double majors (itself a sign to me of more intellectually charged environment) and it didn’t feel quite as pre-professional as a couple of other LACs that we visited. (You can see here that Oberlin is one of the higher producers of PhDs per capita. Grinnell is still higher on this list. The other schools that you’re considering – w/ the exception of Pitt – don’t make the list at all.)
We never visited Grinnell, although at the outset I was hoping to. It didn’t fit into our first tour of midwestern liberal arts colleges and soon thereafter our son announced that he probably wanted to study engineering and so it became moot. But our cousin who went there (shy, nerdy, very into fiber arts, theater, Arthurian legends, baking with artisanal grains, and creative reenactment) loved it and found her people there (there are going to be other people there too – I think even at Grinnell her interests were somewhat niche.)
I don’t think either school registers very high on the post-college earnings surveys. But depending on your child’s goals, I think both should be seriously considered – especially if he liked St. John’s.