I'm an Oberlin student and will just chime in to a few things already mentioned here. I feel like the academics here are great and students really challenge themselves to think. I don't think there is a particular sense here of being "different just to be different." It's really more that everyone feels comfortable to be themselves and that they don't necessarily have to fit in to a certain classification like "hippy" or "jock."
I have friends at both the other schools and while we don't keep in touch so much any more, it seems like they're really enjoying their experiences at their respective schools as well. But I guess to reflect on your perceived differences - I'm quite happy with the size of Oberlin and think that it is intimate without being overly so. I'm not sure if I would like a school much smaller (this is just a personal choice though). Also, there are definitely times I wish that Oberlin were in a city just to get off of campus and have access to some different events and opportunities, but there are some nice things about the pace of life and feeling of security here as well. Good luck with your decision!