Actually, I think there are more similarities between HY than there are differences.
For my kids, the difference came down to “social tone.” The social tone of a college, in part, results from decisions, large and small, made by the administration on issues such as physical space and its use, housing, how freshman are welcomed and integrated into campus life, what role upperclass students play as advisors and mentors, what role graduate students play, how readily faculty members volunteer to host events or trips, etc.
IMHO, Yale’s four-year residential college system fosters a “big-sib, little-sib” feeling to the campus that is missing from Harvard. Every freshman at Yale is welcomed into a residential college, with it’s master and dean, and is allowed to participate in house events. That’s not true at Harvard because it has a three-year residential college system which doesn’t include freshman, who are housed and fed separately in Harvard Yard. As a result, there is somewhat of a disconnect between the experiences of the Harvard freshman class and the experiences of the rest of the student body. It’s almost as if there are two separate student bodies at the school.
But yes, I agree, that a student can be happy at either school!